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4. Hydrothermal eruption dynamics reflecting vertical variations in host rock geology and geothermal alteration, Champagne Pool, Wai-o-tapu, New Zealand

Author

Gallagher, Anna, Montanaro, Cristian, Cronin, Shane, Scott, Bradley, Dingwell, Donald B., Scheu, Bettina, School of Environment, Science Centre, University of Auckland, Auckland Central, New Zealand, Ludwig-Maximilians-Universität München, Munich, Germany, and GNS Science, Wairakei, New Zealand

Subjects
Horizon (geology), geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Lithology, Geothermal, Champagne pool, Geochemistry, Eruption dynamics, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, Experimental, Impact crater, Volcano, 13. Climate action, Geochemistry and Petrology, Breccia, ddc:550.724, Champagne Pool, Ejecta, Hydrothermal eruptions, Geology, 0105 earth and related environmental sciences
Abstract

Hydrothermal eruptions are characterised by violent explosions ejecting steam, water, mud, and rock. They pose a risk to tourism and the operation of power plants in geothermal areas around the world. Large events with a severe destructive threat are often intensified by the injection of magmatic fluids along faults and fractures within volcano-tectonic rifting environments, such as the Taupo Volcanic Zone. How these hydrothermal eruptions progress, how craters form and the scale of ejecta impacts, are all influenced by the local geology and reservoir hydrology. By analysing breccia lithology, undisturbed strata proximal to the explosion sites, and conducting tailored decompression experiments, we elucidate the eruption sequence that formed Champagne Pool, Wai-o-tapu, New Zealand. This iconic touristic site was formed by a violent hydrothermal eruption at ~ 700 years B.P. Samples from undisturbed drill cores and blocks ejected in the eruption were fragmented in shock-tube experiments under the moderate pressure/temperature conditions estimated for this system (3–4 MPa, 210–220 °C). Our results show that this was a two-phase eruption. It started with an initial narrow jetting of deep-sourced lithologies, ejecting fragments from at least a 110-m depth. This event was overtaken by a larger, broader, and dominantly shallower eruption driven by decompression of much more geothermal fluid within a soft and porous ignimbrite horizon. The second phase was triggered once the initial, deeper-sourced eruption broke through a strong silicified aquitard cap. The soft ignimbrite collapsed during the second-phase eruption into the crater, to repeatedly choke the explosions causing short-term pressure rises that triggered ongoing deeper-sourced eruptions. The eruption spread laterally also by exploiting a local fault. These results are relevant for hydrothermal eruption hazard scenarios in environments where strong vertical variations in rock strength and porosity occur., Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659, Ministry of Business, Innovation and Employment http://dx.doi.org/10.13039/501100003524

Published
2020

5. Development of a global seismic risk model

Author

Universidad EAFIT. Departamento de Ingeniería de Producción, Materiales de Ingeniería, Global Earthquake Model Foundation, Acevedo, A., EUCENTRE, GNS Science, US Geological Survey, Natural Resources of Canada, GFZ Potsdam, Universidad EAFIT. Departamento de Ingeniería de Producción, Materiales de Ingeniería, Global Earthquake Model Foundation, Acevedo, A., EUCENTRE, GNS Science, US Geological Survey, Natural Resources of Canada, and GFZ Potsdam

Abstract

Since 2015, the Global Earthquake Model (GEM) Foundation and its partners have been supporting regional programs and bilateral collaborations to develop an open global earthquake risk model. These efforts led to the development of a repository of probabilistic seismic hazard models, a global exposure dataset comprising structural and occupancy information regarding the residential, commercial and industrial buildings, and a comprehensive set of fragility and vulnerability functions for the most common building classes. These components were used to estimate probabilistic earthquake risk globally using the OpenQuake-engine, an open-source software for seismic hazard and risk analysis. This model allows estimating a number of risk metrics such as annualized average losses or aggregated losses for particular return periods, which are fundamental to the development and implementation of earthquake risk mitigation measures. © The Author(s) 2020.

Published
2019

6. The Norfolk Ridge: A Proximal Record of the Tonga‐Kermadec Subduction Initiation

Author

J. Collot, R. Sutherland, S. Etienne, M. Patriat, W. R. Roest, B. Marcaillou, C. Clerc, W. Stratford, N. Mortimer, C. Juan, A. Bordenave, P. Schnurle, D. Barker, S. Williams, S. Wolf, M. Crundwell, Service Géologique de Nouvelle Calédonie, Geological Survey of New Caledonia, Department of Industry Mines and Energy-Department of Industry Mines and Energy, Victoria University of Wellington, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Geo-Ocean (GEO-OCEAN), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Environnement Méditerranéen et Modélisation des Agro-Hydrosystèmes (EMMAH), Avignon Université (AU)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), GNS Science [Lower Hutt], GNS Science, Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), Douglas Mental Health University Institute [Montréal], McGill University = Université McGill [Montréal, Canada], Institut national des sciences de l'Univers (INSU - CNRS), DIMENC/SGNC (SGNC), Institut des Sciences de la Terre de Paris (iSTeP), and Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Geophysics, [SDU]Sciences of the Universe [physics], Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

Norfolk Ridge bounds the northeastern edge of the continent of Zealandia and is proximal to where Cenozoic Tonga-Kermadec subduction initiation occurred. We present and analyze new seismic reflection, bathymetric and rock data from Norfolk Ridge that show it is composed of a thick sedimentary succession and that it was formed and acquired its present-day ridge physiography and architecture during Eocene to Oligocene uplift, emergence and erosion. Contemporaneous subsidence of the adjacent New Caledonia Trough shaped the western slope of Norfolk Ridge and was accompanied by volcanism. Neogene extension along the eastern slope of Norfolk Ridge led to the opening of the Norfolk Basin. Our observations reveal little or no contractional deformation, in contrast to observations elsewhere in Zealandia, and are hence significant for understanding the mechanics of subduction initiation. We suggest that subduction nucleated north of Norfolk Ridge and propagated rapidly along the ridge during the period 40-35 Ma, giving it a linear and narrow shape. Slab roll-back following subduction initiation may have preserved the ridge and created its eastern flank. Our observations suggest that pre-existing structures, which were likely inherited from Cretaceous Gondwana subduction, were well-oriented to propagate rupture and create self-sustaining subduction. Key Points We present new marine geophysical and geological data of Norfolk Ridge located along the northeastern edge of the Zealandia continent We show that the ridge is not inherited from Cretaceous rifting that led to isolation of Zealandia but from the TECTA Cenozoic tectonic event Analysis of the structure and evolution of Norfolk Ridge underpins our understanding of tectonic processes of subduction initiation Plain Language Summary Plate tectonic theory established and proved that the surface of Earth is composed of rigid moving plates, but it remains unclear how and why these plates sometimes re-configure their boundaries and motions. Subduction zones are places where two plates converge and one plunges deep into the Earth beneath the other one. As the plate sinks, it drags the rest of the plate with it and acts as an engine that “pulls” the plate and drives horizontal motion. This is what drives the dynamics of plate tectonics. How are subduction zones created? This remains an open question, but we know from geological observations that new subduction zones do get created: more than half of all active subduction zones were created after the dinosaurs died out 65 million years ago. We present new observations from northern Zealandia (a submerged continent between New Zealand and New Caledonia) that document how one of the largest subduction zones on Earth, the Tonga-Kermadec system, started.

Published
2023

7. A method for evaluating population and infrastructure exposed to natural hazards: tests and results for two recent Tonga tsunamis

Author

Bruce Thomas, Jean Roger, Salman Ashraf, Yanni Gunnell, Universität Stuttgart [Stuttgart], GNS Science [Lower Hutt], GNS Science, Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Geography, Planning and Development, Management, Monitoring, Policy and Law, Environmental Science (miscellaneous), Geotechnical Engineering and Engineering Geology, Safety, Risk, Reliability and Quality, [SHS]Humanities and Social Sciences
Abstract

Background Coastal communities are highly exposed to ocean- and -related hazards but often lack an accurate population and infrastructure database. On January 15, 2022 and for many days thereafter, the Kingdom of Tonga was cut off from the rest of the world by a destructive tsunami associated with the Hunga Tonga Hunga Ha’apai volcanic eruption. This situation was made worse by COVID-19-related lockdowns and no precise idea of the magnitude and pattern of destruction incurred, confirming Tonga’s position as second out of 172 countries ranked by the World Risk Index 2018. The occurrence of such events in remote island communities highlights the need for (1) precisely knowing the distribution of buildings, and (2) evaluating what proportion of those would be vulnerable to a tsunami. Methods and Results A GIS-based dasymetric mapping method, previously tested in New Caledonia for assessing and calibrating population distribution at high resolution, is improved and implemented in less than a day to jointly map population clusters and critical elevation contours based on runup scenarios, and is tested against destruction patterns independently recorded in Tonga after the two recent tsunamis of 2009 and 2022. Results show that ~ 62% of the population of Tonga lives in well-defined clusters between sea level and the 15 m elevation contour. The patterns of vulnerability thus obtained for each island of the archipelago allow exposure and potential for cumulative damage to be ranked as a function of tsunami magnitude and source area. Conclusions By relying on low-cost tools and incomplete datasets for rapid implementation in the context of natural disasters, this approach works for all types of natural hazards, is easily transferable to other insular settings, can assist in guiding emergency rescue targets, and can help to elaborate future land-use planning priorities for disaster risk reduction purposes.

Published
2023

8. A rapid and low-cost method for evaluating and mapping population and infrastructures exposed to natural hazards

Author

Thomas, Bruce Enki Oscar, Roger, Jean, Gunnell, Yanni, Ashraf, Salman, Universität Stuttgart [Stuttgart], GNS Science [Lower Hutt], GNS Science, Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SHS]Humanities and Social Sciences
Published
2023

9. Assessing late Pliocene climate variability over glacial-interglacial timescales (PlioVAR)

Author

Erin McClymont, Sze Ling Ho, Heather Ford, Sarah White, Jeroen Groenveld, Clara Bolton, Kau Thirumalai, Georgia Grant, Molly Patterson, Montserrat Alonso-Garcia, Babette Hoogakker, Department of Geography, Durham University, Durham University, Institute of Oceanography [Taipei], National Taiwan University [Taiwan] (NTU), SCHOOL OF GEOGRAPHY QUEEN MARY UNIVERSITY OF LONDON GBR, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Department of Earth and Planetary Sciences [Santa Cruz], University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Department of Geosciences [University of Arizona], University of Arizona, GNS Science [Lower Hutt], GNS Science, Department of Geological Sciences and Environmental Studies [Binghamton], Binghamton University [SUNY], and State University of New York (SUNY)-State University of New York (SUNY)

Subjects
[SDE]Environmental Sciences
Abstract

The Pliocene epoch (~2.6-5.3 million years ago) is one of the best resolved examples of a climate state in long-term equilibrium with current or predicted near-future atmospheric CO2 concentrations, characterised by a globally warmer climate, reduced continental ice volume, and reduced ocean/atmosphere circulation intensity compared to today. Towards the end of the Pliocene, there was a marked increase in glaciation in the northern hemisphere and atmospheric CO2 concentrations declined. The Past Global Changes (PAGES) PlioVAR working group aimed to co-ordinate a synthesis of terrestrial and marine data to characterise spatial and temporal variability of Pliocene climate, underpinned by high quality data sets supported by robust stratigraphies. Here we present some of the main findings of this synthesis effort, including new assessments of ocean temperatures during the KM5c interglacial, and recent work assessing orbital-scale climate variability across the late Pliocene-early Pleistocene northern hemisphere ice-sheet growth. We outline our approaches to integrating multi-proxy data recording ocean temperatures, d18O and sea-level variability from a globally distributed suite of marine sediment cores. We explore regional expressions of environmental change across this transition, identifying asynchronous trends and patterns in climate changes. We consider how these results might inform our understanding of past climate forcings and feedbacks during both warm intervals of the past and the development of larger ice sheets in the northern hemisphere.

Published
2022

10. A rapid, low-cost, high-resolution, map-based assessment of the January 15, 2022 tsunami impact on population and buildings in the Kingdom of Tonga

Author

Bruce Enki Oscar Thomas, Jean Roger, Yanni Gunnell, Universität Stuttgart [Stuttgart], GNS Science [Lower Hutt], GNS Science, Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SHS]Humanities and Social Sciences
Abstract

The population and built infrastructure of the Kingdom of Tonga are highly exposed to ocean- and climate-related coastal hazards. The archipelago was impacted on January 15, 2022, by a destructive tsunami caused by the Hunga Tonga-Hunga Ha'apai submarine volcanic eruption. Weeks later, several islands were still cut off from the world, this situation was made worse by covid-19-related international lockdowns and no precise idea of the magnitude and pattern of destruction. Like in most Pacific islands, the Kingdom of Tonga lacks an accurate population and infrastructure database. The occurrence of events such as this in remote island communities highlights the need for (1) precisely knowing the distribution of residential and public buildings, (2) evaluating what proportion of those would be vulnerable to a tsunami depending on various run-up scenarios, (3) providing tools to the local authorities for elaborating efficient evacuation plans and securing essential services outside the hazard zones. Using a GIS-based dasymetric mapping method previously tested in New Caledonia for assessing, calibrating, and mapping population distribution at high resolution, we produce maps that combine population clusters, critical elevation contours, and the precise location of essential services (hospitals, airports, shopping centers, etc.), backed up by before–after imagery accessible online. Results show that 62% of the population on the main island of Tonga lives in well-defined clusters between sea level and the 15 m elevation contour, which is also the value of the maximum tsunami run-up reported on this occasion. The patterns of vulnerability thus obtained for each island in the archipelago, are further compared to the destruction patterns recorded after the earthquake-related 2009 tsunami in Tonga, thereby also allowing us to rank exposure and potential for cumulative damage as a function of tsunami cause and source-area. By relying on low-cost tools and incomplete datasets for rapid implementation in the context of natural disasters, this approach can assist in (1) guiding emergency rescue targets, and (2) elaborating future land-use planning priorities for disaster risk-reduction purposes. By involving an interactive mapping tool to be shared with the resident population, the approach aims to enhance disaster-preparedness and resilience. It works for all types of natural hazards and is easily transferable to other insular settings.

Published
2022

11. A low-cost toolbox for high-resolution vulnerability and hazard-perception mapping in view of tsunami risk mitigation: application to New Caledonia

Author

Bruce Thomas, Catherine Sabinot, Jerome Aucan, Jean Roger, Yanni Gunnell, Ecologie marine tropicale des océans Pacifique et Indien (ENTROPIE [Nouvelle-Calédonie]), Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie])-Ifremer - Nouvelle-Calédonie, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Nouvelle-Calédonie (UNC), École Nationale des Travaux Publics de l'État (ENTPE), École Nationale des Travaux Publics de l'État (ENTPE)-Ministère de l'Ecologie, du Développement Durable, des Transports et du Logement, Environnement, Ville, Société (EVS), École normale supérieure de Lyon (ENS de Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Universität Stuttgart [Stuttgart], GNS Science [Lower Hutt], GNS Science, UMR 228 Espace-Dev, Espace pour le développement, and Institut de Recherche pour le Développement (IRD)-Université de Perpignan Via Domitia (UPVD)-Avignon Université (AU)-Université de La Réunion (UR)-Université de Guyane (UG)-Université des Antilles (UA)-Université de Montpellier (UM)

Subjects
010504 meteorology & atmospheric sciences, Disaster risk reduction, Population, 0211 other engineering and technologies, Vulnerability, Distribution (economics), 02 engineering and technology, 01 natural sciences, [SHS]Humanities and Social Sciences, New Caledonia, Dasymetric map, education, Tsunami hazard, Ecosystems shields, Risk management, 0105 earth and related environmental sciences, 021110 strategic, defence & security studies, education.field_of_study, Perception survey, business.industry, Environmental resource management, Behavioral pattern, Geology, Building and Construction, Geotechnical Engineering and Engineering Geology, Risk perception, Dasymetric population mapping, Geography, Community-based disaster-risk reduction, business, Safety Research
Abstract

International audience; The drive towards improving tsunami risk mitigation has intensified along many populated coastlines. Like many islands in the Pacific Ocean, the coastal population of New Caledonia is exposed to tsunamis triggered by powerful earthquakes. Intersecting exhaustive population data with high-resolution building location data within a user-defined coastal fringe is an accurate means of geolocating vulnerable residents, and an important step towards disaster risk reduction. This paper presents a mixed methodology built on GIS-based dasymetric techniques for assessing, classifying, and mapping population distribution in New Caledonia, with the aim of quantifying and ranking the areas most vulnerable to tsunami-related hazards. Results reveal that 33% of the population, inclusive of previously unmapped precarious housing, lives between sea level and the 10 m elevation contour in well-defined clusters. A pilot field survey of 412 respondents was additionally conducted in the capital Nouméa (66% of the nation's population) to assess tsunami awareness, risk perception, and risk-related behavioral patterns among the ethnically and demographically diverse population. By further mapping the spatial association between coastal population concentrations, the perceived natural shielding capacities of coral reefs and mangroves, and the benefits of alarm siren networks, the study delivers a comprehensive assessment of the country's disaster preparedness, with policy recommendations for the future. The methodology is transferable to other types of hazards and other insular settings where civil security and risk-management organizations acquire and curate reliable primary data but may also need guidelines for transforming them into serviceable disaster risk reduction methods and policies.

Published
2021

12. Dehydration-induced earthquakes identified in a subducted oceanic slab beneath Vrancea, Romania

Author

Thomas P. Ferrand, Elena Florinela Manea, Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Géodynamique - UMR7327, Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), National Institute for Earth Physics [Bucharest] (NIEP), GNS Science [Lower Hutt], GNS Science, and ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010)

Subjects
Solid Earth sciences, 010504 meteorology & atmospheric sciences, Science, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Article, Mantle (geology), Lithosphere, Oceanic crust, Petrology, Seismology, 0105 earth and related environmental sciences, Multidisciplinary, Subduction, Continental crust, Tectonics, Geology, Mineralogy, Geophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Delamination (geology), Slab, Medicine
Abstract

Vrancea, Eastern Romania, presents a significant intermediate-depth seismicity, between 60 and 170 km depth, i.e. pressures from 2 to 6.5 GPa. A debate has been lasting for decades regarding the nature of the seismic volume, which could correspond to the remnant of a subducted slab of Tethyan lithosphere or a delamination of the Carpathians lithosphere. Here we compile the entire seismicity dataset (≈ 10,000 events with 2 ≤ Mw ≤ 7.9) beneath Vrancea for P > 0.55 GPa (> 20 km) since 1940 and estimate the pressure and temperature associated with each hypocenter. We infer the pressure and temperature, respectively, from a depth-pressure conversion and from the most recent tomography-based thermal model. Pressure–temperature diagrams show to what extent these hypocentral conditions match the thermodynamic stability limits for minerals typical of the uppermost mantle, oceanic crust and lower continental crust. The stability limits of lawsonite, chloritoid, serpentine and talc minerals show particularly good correlations. Overall, the destabilization of both mantle and crustal minerals could participate in explaining the observed seismicity, but mantle minerals appear more likely with more convincing correlations. Most hypocentral conditions match relatively well antigorite dehydration between 2 and 4.5 GPa; at higher pressures, the dehydration of the 10-Å phase provides the best fit. We demonstrate that the Vrancea intermediate-depth seismicity is evidence of the current dehydration of an oceanic slab beneath Romania. Our results are consistent with a recent rollback of a W-dipping oceanic slab, whose current location is explained by limited delamination of the continental Moesian lithosphere between the Tethyan suture zone and Vrancea.

Published
2021

13. Sr, Nd, Hf and Pb isotope geochemistry of Early Miocene shoshonitic lavas from the South Fiji Basin: note

Author

Nick Mortimer, Delphine Bosch, James B. Gill, Erin Todd, Christine Laporte-Magoni, GNS Science [Lower Hutt], GNS Science, Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Exactes et Appliquées, and Université Polytechnique Nazi Boni Bobo-Dioulasso (UNB)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, Seamount, Geochemistry, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, Pacific ocean, Geophysics, Back-arc basin, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Isotope geochemistry, [SDE]Environmental Sciences, Earth and Planetary Sciences (miscellaneous), [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We present new Sr, Nd, Hf and Pb isotope data for Early Miocene shoshonitic and high-K lavas dredged from seamounts in the South Fiji Basin, southwest Pacific Ocean. Our analyses provide a useful r...

Published
2021

14. Shelf-derived mass-transport deposits: origin and significance in the stratigraphic development of trench-slope basins

Author

Julien Bailleul, Hugh E. G. Morgans, Geoffroy Mahieux, Frank Chanier, Corentin Chaptal, Bruno C. Vendeville, Adam D. McArthur, B. Claussmann, Vincent Caron, UniLaSalle, Bassins - Réservoirs - Ressources - U2R UPJV-UNIL 7511 (B2R), Université de Picardie Jules Verne (UPJV)-UniLaSalle, Schlumberger, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), University of Leeds, GNS Science [Lower Hutt], GNS Science, and Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Mass transport, 010504 meteorology & atmospheric sciences, shelf failure, 010502 geochemistry & geophysics, 01 natural sciences, Paleontology, active margin, Passive margin, Earth and Planetary Sciences (miscellaneous), tectonics, outcrop study, [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, geography, geography.geographical_feature_category, intra-slope basins, Continental shelf, Geology, Tectonics, Geophysics, 13. Climate action, [SDU]Sciences of the Universe [physics], [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Trench, mass-wasting deposits
Abstract

The data that support the findings of this study are openly available in figshare at: https://figshare.com/articles/journal_contribution/Claussmann_et_al_NZJGG_Supplementary_material/13614101; International audience; Continental shelves generally supply large-scale mass-wasting events. Yet, the origin and significance of shelf-derived mass-transport deposits (MTDs) for the tectonostratigraphic evolution of subduction complexes and their trench-slope basins have not been extensively studied. Here, we present high-resolution, outcrop-scale insights on both the nature of the reworked sediments, and their mechanisms of development and emplacement along tectonically active margins, by examining the Middle Miocene shelf-derived MTDs outcropping in the exhumed southern portion of the Hikurangi subduction margin. Results show that periods of repeated tectonic activity (thrust propagation, uplift) in such compressional settings not only affect and control the development of shelfal environments but also drive the recurrent generation and destruction of oversteepened slopes, which in turn, favour the destabilisation and collapses of the shelves and their substratum. Here, these events produced both large-scale, shelf-derived sediment mass-failures and local debris flows, which eventually broke down into a series of coalescing, erosive, genetically linked surging flows downslope. The associated MTDs have a regional footprint, being deposited across several trench-slope basins. Recognition of tectonic activity as another causal mechanism for large-scale shelf failure (in addition to sea-level changes, high-sedimentation fluxes) has implications for both stratigraphic predictions and understanding the tectonostratigraphic evolution of deep-marine fold-and-thrust belts.

Published
2021

15. The Influence of Near-field Fluxes on Seasonal Carbon Dioxide Enhancements: Results From the Indianapolis Flux Experiment (INFLUX)

Author

Jianming Liang, Douglas K. Martins, Kenneth J. Davis, Natasha L. Miles, Aijun Deng, Nikolay V. Balashov, Geoffrey Roest, Jocelyn Turnbull, Scott J. Richardson, Kevin R. Gurney, Jonathan A. Wang, Thomas Lauvaux, Pennsylvania State University (Penn State), Penn State System, Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Northern Arizona University [Flagstaff], Boston University [Boston] (BU), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), NASA Goddard Space Flight Center (GSFC), University of California [Irvine] (UCI), University of California, GNS Science [Lower Hutt], GNS Science, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado [Boulder]-National Oceanic and Atmospheric Administration (NOAA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of California [Irvine] (UC Irvine), and University of California (UC)

Subjects
INFLUX, 010504 meteorology & atmospheric sciences, Growing season, Land cover, 010501 environmental sciences, Management, Monitoring, Policy and Law, Atmospheric sciences, 01 natural sciences, 7. Clean energy, anthropogenic, Flux (metallurgy), Earth and Planetary Sciences (miscellaneous), medicine, Ecosystem, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, background, Research, Vegetation, Seasonality, 15. Life on land, medicine.disease, fluxes, Carbon dioxide, 13. Climate action, greenhouse gas, Greenhouse gas, Drawdown (hydrology), General Earth and Planetary Sciences, Environmental science, biogenic, urban
Abstract

Background Networks of tower-based CO2 mole fraction sensors have been deployed by various groups in and around cities across the world to quantify anthropogenic CO2 emissions from metropolitan areas. A critical aspect in these approaches is the separation of atmospheric signatures from distant sources and sinks (i.e., the background) from local emissions and biogenic fluxes. We examined CO2 enhancements compared to forested and agricultural background towers in Indianapolis, Indiana, USA, as a function of season and compared them to modeled results, as a part of the Indianapolis Flux (INFLUX) project. Results At the INFLUX urban tower sites, daytime growing season enhancement on a monthly timescale was up to 4.3–6.5 ppm, 2.6 times as large as those in the dormant season, on average. The enhancement differed significantly depending on choice of background and time of year, being 2.8 ppm higher in June and 1.8 ppm lower in August using a forested background tower compared to an agricultural background tower. A prediction based on land cover and observed CO2 fluxes showed that differences in phenology and drawdown intensities drove measured differences in enhancements. Forward modelled CO2 enhancements using fossil fuel and biogenic fluxes indicated growing season model-data mismatch of 1.1 ± 1.7 ppm for the agricultural background and 2.1 ± 0.5 ppm for the forested background, corresponding to 25–29% of the modelled CO2 enhancements. The model-data total CO2 mismatch during the dormant season was low, − 0.1 ± 0.5 ppm. Conclusions Because growing season biogenic fluxes at the background towers are large, the urban enhancements must be disentangled from the biogenic signal, and growing season increases in CO2 enhancement could be misinterpreted as increased anthropogenic fluxes if the background ecosystem CO2 drawdown is not considered. The magnitude and timing of enhancements depend on the land cover type and net fluxes surrounding each background tower, so a simple box model is not appropriate for interpretation of these data. Quantification of the seasonality and magnitude of the biological fluxes in the study region using high-resolution and detailed biogenic models is necessary for the interpretation of tower-based urban CO2 networks for cities with significant vegetation.

Published
2021

16. Technical note: A new automated radiolarian image acquisition, stacking, processing, segmentation and identification workflow

Author

Luc Beaufort, Martin Tetard, Thibault de Garidel-Thoron, Y. Gally, Giuseppe Cortese, Ross Marchant, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), GNS Science [Lower Hutt], GNS Science, ANR-10-EQPX-0039,NanoID,Plateforme d'identification des nanoparticules dédiée à la sécurité(2010), ANR-15-CE40-0006,CoMeDiC,Métriques convergentes pour le calcul digital(2015), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)

Subjects
010506 paleontology, Computer science, lcsh:Environmental protection, Stratigraphy, Interface (computing), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Image processing, 010502 geochemistry & geophysics, 01 natural sciences, Convolutional neural network, Digital image, Software, lcsh:Environmental pollution, lcsh:TD169-171.8, Segmentation, Computer vision, lcsh:Environmental sciences, 0105 earth and related environmental sciences, lcsh:GE1-350, Global and Planetary Change, business.industry, Paleontology, Identification (information), Workflow, lcsh:TD172-193.5, Artificial intelligence, business, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract

Identification of microfossils is usually done by expert taxonomists and requires time and a significant amount of systematic knowledge developed over many years. These studies require manual identification of numerous specimens in many samples under a microscope, which is very tedious and time-consuming. Furthermore, identification may differ between operators, biasing reproducibility. Recent technological advances in image acquisition, processing and recognition now enable automated procedures for this process, from microscope image acquisition to taxonomic identification. A new workflow has been developed for automated radiolarian image acquisition, stacking, processing, segmentation and identification. The protocol includes a newly proposed methodology for preparing radiolarian microscopic slides. We mount eight samples per slide, using a recently developed 3D-printed decanter that enables the random and uniform settling of particles and minimizes the loss of material. Once ready, slides are automatically imaged using a transmitted light microscope. About 4000 specimens per slide (500 per sample) are captured in digital images that include stacking techniques to improve their focus and sharpness. Automated image processing and segmentation is then performed using a custom plug-in developed for the ImageJ software. Each individual radiolarian image is automatically classified by a convolutional neural network (CNN) trained on a Neogene to Quaternary radiolarian database (currently 21 746 images, corresponding to 132 classes) using the ParticleTrieur software. The trained CNN has an overall accuracy of about 90 %. The whole procedure, including the image acquisition, stacking, processing, segmentation and recognition, is entirely automated via a LabVIEW interface, and it takes approximately 1 h per sample. Census data count and classified radiolarian images are then automatically exported and saved. This new workflow paves the way for the analysis of long-term, radiolarian-based palaeoclimatic records from siliceous-remnant-bearing samples.

Published
2020

17. A new automated radiolarian image acquisition, stacking, processing, segmentation, and identification workflow

Author

Ross Marchant, Y. Gally, Giuseppe Cortese, Martin Tetard, Luc Beaufort, Thibault de Garidel-Thoron, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), School of Engineering and Robotic, University of Queensland [Brisbane], GNS Science [Lower Hutt], GNS Science, and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
010506 paleontology, business.industry, Computer science, Interface (computing), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Image processing, 01 natural sciences, Convolutional neural network, Identification (information), Digital image, Software, Workflow, [SDE]Environmental Sciences, Segmentation, Computer vision, Artificial intelligence, business, 0105 earth and related environmental sciences
Abstract

Identification of microfossils is usually done by expert taxonomists and requires time and a significant amount of systematic knowledge developed over many years. These studies require manual identification of numerous specimens in many samples under a microscope, which is very tedious and time consuming. Furthermore, identification may differ between operators, biasing reproducibility. Recent technological advances in image acquisition, processing, and recognition now enable automated procedures for this process, from microscope image acquisition to taxonomic identification. A new workflow was developed for automated radiolarian image acquisition, stacking, processing, segmentation, and identification. The protocol includes a newly proposed methodology for preparing radiolarian microscopic slides. We mount 8 samples per slide, using a recently developed 3D-printed decanter that enable the random and uniform settling of particles, and minimise the loss of material. Once ready, slides are automatically imaged using a transmitted light microscope. About 4000 specimens per slide (500 per sample) are captured in digital images which include stacking techniques to improve their focus and sharpness. Automated image processing and segmentation is then performed using a custom plugin developed for the ImageJ software. Each individual radiolarian image is automatically classified by a convolutional neural network (CNN) trained on a radiolarian database (currently 17,065 images, corresponding to 112 classes) using the software, ParticleTrieur. The trained CNN has an overall accuracy of about 90 %. The whole procedure, including the image acquisition, stacking, processing, segmentation and recognition, is entirely automated via a LabVIEW interface, and takes approximately 1 hour per sample. Census data count and classified radiolarian images are then automatically exported and saved. This new workflow paves the way for the analysis of long-term, radiolarian-based palaeoclimatic records from siliceous remains-bearing samples.

Published
2020

18. Seagrass-related carbonate ramp development at the front of a fan delta (Burdigalian, New Caledonia): Insights into mixed carbonate-siliciclastic environments

Author

Hugh E. G. Morgans, François Fournier, Samuel Etienne, Bertrand Martin-Garin, Martin Patriat, Juan C. Braga, Pierre Maurizot, Brice Sevin, E. Tournadour, Julien Collot, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Groupe d'Etudes de Métallurgie Physique et Physique des Matériaux (GEMPPM), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Geological Survey of New Caledonia, Department of Industry Mines and Energy, GNS Science [Lower Hutt], GNS Science, University of Granada [Granada], Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), and Universidad de Granada = University of Granada (UGR)

Subjects
Alluvial fan, 010504 meteorology & atmospheric sciences, Stratigraphy, Geochemistry, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, Tropical carbonates, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Sedimentary depositional environment, chemistry.chemical_compound, New Caledonia, Aggradation, 14. Life underwater, Seagrass, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Terrigenous sediment, Facies association, Geology, Miocene, Geophysics, Terrigenous inputs, chemistry, 13. Climate action, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Carbonate, Economic Geology, Siliciclastic, Sedimentary rock, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, [SDU.OTHER]Sciences of the Universe [physics]/Other, Marine transgression
Abstract

International audience; Past shallow-water carbonate environments of the main island of New Caledonia (NC) have been subject to high terrigenous influx derived from the erosion of ultramafic obducted nappes and are therefore a relevant case study for characterizing neritic carbonate production in mixed carbonate-siliciclastic systems under a tropical climate. More particularly, we focused on Burdigalian carbonate sedimentary records cropping out on the western coast of NC, in the Nepoui area. Based on a comprehensive sedimentological study of cores and outcrops, we established a new depositional model of an alluvial fan to carbonate ramp transition. Shallow-water (euphotic) carbonate production was dominated by seagrass-related biota and corals derived from small-sized bioconstructions. Extensional tectonics and associated normal faulting, driven by post-obduction isostatic rebound, favored carbonate ramp aggradation and preservation. The carbonate ramp was incised by conglomerate-filled terminal distributary channels, which indicate that terrigenous inputs remained significant during marine transgression and did not inhibit the development of seagrass and scleractinian carbonate factories. Phytal substrates induced by seagrass and/or macro-algae seafloor colonization strongly controlled the nature of carbonate production and promoted the accumulation of foraminiferal-coralline algal sediments. Seagrass development at the front of the fan delta is interpreted to have controlled the preservation of a diverse and significant carbonate production by reducing water turbidity and by limiting the risk of suffocation for filter-feeding biota in such a high terrigenous influx setting.

Published
2020

19. A Global Database of Strong‐Motion Displacement GNSS Recordings and an Example Application to PGD Scaling

Author

Yehuda Bock, Mario Ruiz, Marino Protti, Dara E. Goldberg, Emma M. Hill, C. J. Ruhl, Sergio Barrientos, Elisabetta D'Anastasio, Jianghui Geng, Brendan W. Crowell, Jean‐Phillipe Avouac, Sebastian Riquelme, Diego Melgar, Patricia Mothes, Athanassios Ganas, Xyoli Pérez-Campos, Enrique Cabral-Cano, Juan Carlos Baez, Richard M. Allen, Jean-Mathieu Nocquet, Paul Jarrin, Earth Observatory of Singapore, Berkeley Seismological Laboratory [Berkeley], University of California [Berkeley], University of California-University of California, Wuhan University [China], University of California [San Diego] (UC San Diego), University of California, Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Centro Sismológico Nacional, Universidad de Chile, Facultad de Ciencas, Universitad Nacional Autonoma de Mexico, Mexico, Earth Observatory of Singapore (EOS), Nanyang Technological University [Singapour], Observatorio Vulcanológicoy Sismológico de Costa Rica, Universidad Nacional de Costa Rica, National Observatory of Athens (NOA), Instituto Geofísico, Escuela Politécnica Nacional (EPN), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), California Institute of Technology (CALTECH), GNS Science [Lower Hutt], and GNS Science

Subjects
Global Navigation Satellite System, Earthquake, 010504 meteorology & atmospheric sciences, Database, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Magnitude (mathematics), Satellite system, 010502 geochemistry & geophysics, computer.software_genre, Accelerometer, 01 natural sciences, Displacement (vector), Environmental engineering [Engineering], Geophysics, Data point, GNSS applications, Range (statistics), Waveform, computer, Geology, 0105 earth and related environmental sciences
Abstract

Displacement waveforms derived from Global Navigation Satellite System (GNSS) data have become more commonly used by seismologists in the past 15 yrs. Unlike strong‐motion accelerometer recordings that are affected by baseline offsets during very strong shaking, GNSS data record displacement with fidelity down to 0 Hz. Unfortunately, fully processed GNSS waveform data are still scarce because of limited public availability and the highly technical nature of GNSS processing. In an effort to further the use and adoption of high‐rate (HR) GNSS for earthquake seismology, ground‐motion studies, and structural monitoring applications, we describe and make available a database of fully curated HR‐GNSS displacement waveforms for significant earthquakes. We include data from HR‐GNSS networks at near‐source to regional distances (1–1000 km) for 29 earthquakes between Mw 6.0 and 9.0 worldwide. As a demonstration of the utility of this dataset, we model the magnitude scaling properties of peak ground displacements (PGDs) for these events. In addition to tripling the number of earthquakes used in previous PGD scaling studies, the number of data points over a range of distances and magnitudes is dramatically increased. The data are made available as a compressed archive with the article. The authors thank Ronni Grapenthin and Valerie Sahakian for helpful discussions on the peak ground displacement (PGD) scaling law and residuals. This work was funded by the Gordon and Betty Moore Foundation through Grant GBMF3024 to University of California (UC) Berkeley and the U.S. Geological Survey Grants G16AC00348 and G17AC00346 to UC Berkeley. Work was also done under Grant 41674033 from the National Science Foundation of China. Scripps Orbit and Permanent Array Center (SOPAC) work was funded by NASA Grants NNH17ZDA001N, NNX16AM04A and NNX17AD99G and National Science Foundation (NSF) Grant EAR-1400. The authors thank the Geospatial Information Authority of Japan for operation and maintenance of the GEONET Global Positioning System (GPS) network whose data are used in this study. The authors gratefully acknowledge all the personnel from Servicio Sismologico Nacional (SSN), Servicio de Geodesia Satelital (SGS) and UNAVCO Inc. for GPS station maintenance, data acquisition, IT support and data distribution. The authors acknowledge the New Zealand GeoNet project and its sponsors EQC, GNS Science, and LINZ, for providing data used in this study.

Published
2018

20. Stratigraphy and Tectonics of the Continental Norfolk Ridge, SW Pacific Ocean

Author

Collot, Julien, Roest, Walter, Sutherland, Rupert, Patriat, Martin, Etienne, Samuel, Bordenave, Aurélien, Marcaillou, Boris, Schnurle, Philippe, Juan, Caroline, Barker, Dan, Stratford, Wanda Rose, Williams, Simon J., Wolf, Sylvie, Clerc, Camille, Crundwell, Martin, Service de la Géologie de Nouvelle Calédonie, Direction de l'Industrie, des Mines et de l'Energie de Nouvelle Calédonie, Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), GNS Science [Lower Hutt], GNS Science, Géoressources et environnement, Institut Polytechnique de Bordeaux (Bordeaux INP)-Université Bordeaux Montaigne, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Laboratoire de Géosciences Marines (LGM), Université Pierre et Marie Curie - Paris 6 (UPMC)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Warwick [Coventry], IFP Energies nouvelles (IFPEN), Université de la Nouvelle-Calédonie (UNC), and AGU

Subjects
[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; The Norfolk Ridge is a north-south trending ca. 1000 x 80 km bathymetric high located along the easternmost edge of the Zealandia continent at ca. 1 km water-depth. It lies in a key tectonic position which marks the boundary between Neogene subduction-related arcs and backarc basins to the east (e.g. 3-4 km deep Norfolk Basin) and Mesozoic to Paleogene continental basins to the west (e.g. 2-3 km deep New Caledonia and Reinga basins). The ridge is emergent in New Caledonia and New Zealand where obduction is known to have occurred in the late Paleogene to early Neogene. It is also hypothesized to be proximal to where the Tonga Kermadec Subduction initiated. Yet, the structure, geology and stratigraphy of the Norfolk Ridge remain largely unknown. New geophysical and geological data from the TECTA and VESPA voyages acquired in 2015 onboard RV L’Atalante reveal the structural style and stratigraphy of the ridge. It is composed of a thick sedimentary succession perched between the Norfolk and New Caledonia basins. Two main seismic units are observed. The lower unit (NR1) is thick (> 2 s twt), tilted east towards the Norfolk Basin and its top is marked by a major erosional unconformity. The upper unit (NR2) is thinner (< 0.5 s twt), likely composed of hemipelagic sediments affected by deep sea currents; and hence it drapes the ridge unevenly, exposing NR1 on the seafloor in many places. Some VESPA rock dredges were made accross the unconformity and sampled Oligocene shallow water carbonates. Volcanoes are prominent in several sectors of the ridge and post-date the erosional unconformity. Both the eastern and western margins of the ridge are affected by normal faulting that also seemingly post-dates the erosional event. No evidence of contractional deformation is observed on the ridge, except very locally close to New Caledonia and within Reinga Basin where contraction is widespread. Collectively these new observations indicate the ridge underwent important vertical motions (>1 km) that in the Eocene-Oligocene, but – surprisingly – without evidences for contraction. These events were closely followed by, or synchronous with, a volcanic episode and normal faulting that formed the ridge’s present-day morphology. This calls into question the modalities of the induced subduction initiation model that is proposed for the region.

Published
2019

21. Atmosphere‐Ocean CO2 Exchange Across the Last Deglaciation from the Boron Isotope Proxy

Author

James W. B. Rae, Helen L. Neil, Lowell D. Stott, Richard B. Coffin, Jun Shao, Ingo Pecher, William R Gray, Bryan Davy, Rosanna Greenop, University of Southern California (USC), School of Earth and Environmental Sciences [University St Andrews], University of St Andrews [Scotland], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), School of Environment [Auckland, New Zealand], University of Auckland [Auckland], National Institute of Water and Atmospheric Research [Auckland] (NIWA), Texas A&M University [Corpus Christi], GNS Science [Lower Hutt], GNS Science, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), NERC, University of St Andrews. School of Earth & Environmental Sciences, and University of St Andrews. St Andrews Isotope Geochemistry

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, GE, 010504 meteorology & atmospheric sciences, NDAS, Paleontology, Isotopes of boron, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Proxy (climate), 13. Climate action, Paleoceanography, Paleoclimatology, Deglaciation, SDG 13 - Climate Action, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Co2 exchange, Geology, 0105 earth and related environmental sciences, GE Environmental Sciences, SDG 15 - Life on Land
Abstract

J. Shao and L.D. Stott were supported by an NSF grant (MG&G 1558990). W. R. Gray and R. Greenop were supported by NERC grants NE/N011716/1 and NE/N011716/1 to J.W.B. Rae. I. Pecher, H.L. Neil, and B. Davy were supported by RSNZ Marsden Fund grant UOA1022. R. Coffin was supported by a DOE-NETL contract to NRL subcontract to TAMUCC (#601970). Identifying processes within the Earth System that have modulated atmospheric pCO2 during each glacial cycle of the late Pleistocene stands as one of the grand challenges in climate science. The growing array of surface ocean pH estimates from the boron isotope proxy across the last glacial termination may reveal regions of the ocean that influenced the timing and magnitude of pCO2 rise. Here we present two new boron isotope records from the subtropical‐subpolar transition zone of the Southwest Pacific that span the last 20 kyr, as well as new radiocarbon data from the same cores. The new data suggest this region was a source of carbon to the atmosphere rather than a moderate sink as it is today. Significantly higher outgassing is observed between ~16.5‐14 kyrBP, associated with increasing δ13C and [CO3]2‐ at depth, suggesting loss of carbon from the intermediate ocean to the atmosphere. We use these new boron isotope records together with existing records to build a composite pH/pCO2 curve for the surface oceans. pH disequilibrium/CO2 outgassing was widespread throughout the last deglaciation, likely explained by upwelling of CO2 from the deep/intermediate ocean. During the Holocene, a smaller outgassing peak is observed at a time of relatively stable atmospheric CO2, which may be explained by regrowth of the terrestrial biosphere countering ocean CO2 release. Our stack is likely biased toward upwelling/CO2 source regions. Nevertheless, the composite pCO2 curve provides robust evidence that various parts of the ocean were releasing CO2 to the atmosphere over the last 25 kyr. Publisher PDF

Published
2019

23. Inter-laboratory test for oxygen and hydrogen stable isotope analyses of geothermal fluids: Assessment of reservoir fluid compositions

Author

Roslanzairi Mostapa, Robert van Geldern, José Marcus Godoy, Mahendra P. Verma, Gaël Monvoisin, Thomas Kretzschmar, Hugo Alberto Durán Cortés, Daniel Carrizo, Johannes A. C. Barth, Ruth Esther Villanueva-Estrada, Fausto Grassa, Antonio Delgado Huertas, Karyne M. Rogers, GeoZentrum Nordbayern, Applied Geosciences, Universität Erlangen-Nürnberg - Erlangen, Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, and Universitad de Chile, Santiago

Subjects
Isotope, Hydrogen, Chemistry, Stable isotope ratio, 010401 analytical chemistry, Organic Chemistry, Analytical chemistry, Separator (oil production), chemistry.chemical_element, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010501 environmental sciences, Total dissolved solids, 01 natural sciences, Oxygen, 6. Clean water, 0104 chemical sciences, Analytical Chemistry, 13. Climate action, Isotope-ratio mass spectrometry, Geothermal gradient, Spectroscopy, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Rationale Knowledge of the accuracy and precision for oxygen (δ18 O values) and hydrogen (δ2 H values) stable isotope analyses of geothermal fluid samples is important to understand geothermal reservoir processes, such as partial boiling-condensation and encroachment of cold and reinjected waters. The challenging aspects of the analytical techniques for this specific matrix include memory effects and higher scatter of delta values with increasing total dissolved solids (TDS) concentrations, deterioration of Pt-catalysts by dissolved/gaseous H2 S for hydrogen isotope equilibration measurements and isotope salt effects that offset isotope ratios determined by gas equilibration techniques. Methods An inter-laboratory comparison exercise for the determination of the δ18 O and δ2 H values of nine geothermal fluid samples was conducted among eleven laboratories from eight countries (CeMIEGeo2017). The delta values were measured by dual inlet isotope ratio mass spectrometry (DI-IRMS), continuous flow IRMS (CF-IRMS) and/or laser absorption spectroscopy (LAS). Moreover, five of these laboratories analyzed an additional sample set at least one month after the analysis period of the first set. Statistical evaluation of all the results was performed to obtain the expected isotope ratios of each sample, which were then subsequently used in deep reservoir fluid composition calculations. Results The overall analytical precisions of the measurements were ± 0.2‰ for δ18 O values and ± 2.0‰ for δ2 H values within the 95% confidence interval. Conclusions The measured and calculated δ18 O and δ2 H values of water sampled at the weir box, separator and wellhead of geothermal wells suggest the existence of hydrogen and oxygen isotope-exchange equilibrium between the liquid and vapor phases at all sampling points in the well. Thus, both procedures for calculating the isotopic compositions of the deep geothermal reservoir fluid - using either the analytical data of the liquid phase at the weir box together with those of vapor at the separator or the analytical data of liquid and vapor phases at the separator -are equally valid.

Published
2018

24. Earthquake nucleation and fault slip complexity in the lower crust of central Alaska

Author

Yoshihiro Kaneko, Vipul Silwal, Jean-Paul Ampuero, S. G. Holtkamp, Chen Ji, Carl Tape, Michael West, Kyle Smith, J. C. Hawthorne, Natalia A. Ruppert, The Geophysical Institute University of Alaska Fairbanks 903 Koyukuk Ave Fairbanks, University of Alaska [Fairbanks] (UAF), Department of Earth Sciences [Oxford], University of Oxford [Oxford], GNS Science [Lower Hutt], GNS Science, California Institute of Technology (CALTECH), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), University of California [Santa Barbara] (UCSB), University of California, Geophysical Institute, Geophysical Institute [Fairbanks], Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, Nucleation, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Slip (materials science), Fault (geology), Geodynamics, 010502 geochemistry & geophysics, 01 natural sciences, Foreshock, Physics::Geophysics, Tectonics, 13. Climate action, Epicenter, General Earth and Planetary Sciences, Geology, Seismology, 0105 earth and related environmental sciences
Abstract

International audience; Earthquakes start under conditions that are largely unknown. In laboratory analogue experiments and continuum models, earthquakes transition from slow-slipping, growing nucleation to fast-slipping rupture. In nature, earthquakes generally start abruptly, with no evidence for a nucleation process. Here we report evidence from a strike-slip fault zone in central Alaska of extended earthquake nucleation and of very-low-frequency earthquakes (VLFEs), a phenomenon previously reported only in subduction zone environments. In 2016, a VLFE transitioned into an earthquake of magnitude 3.7 and was preceded by a 12-hour-long accelerating foreshock sequence. Benefiting from 12 seismic stations deployed within 30 km of the epicentre, we identify coincident radiation of distinct high-frequency and low-frequency waves during 22 s of nucleation. The power-law temporal growth of the nucleation signal is quantitatively predicted by a model in which high-frequency waves are radiated from the vicinity of an expanding slow slip front. The observations reveal the continuity and complexity of slip processes near the bottom of the seismogenic zone of a strike-slip fault system in central Alaska.

Published
2018

25. Palaeoclimate constraints on the impact of 2 °c anthropogenic warming and beyond

Author

Martin Ziegler, Johannes Sutter, Thibaut Caley, Katarzyna Marcisz, Giuseppe Cortese, Maria Fernanda Sanchez Goñi, Anne de Vernal, Jacqueline Austermann, Alessio Rovere, Katrin J. Meissner, Carlo Barbante, Basil A. S. Davis, Paul J. Valdes, Anders E. Carlson, Bette L. Otto-Bliesner, Samuel L Jaccard, Jesper Sjolte, Eric W. Wolff, Stéphane Affolter, Sarah A. Finkelstein, Willy Tinner, Nerilie J. Abram, Thomas Felis, Zicheng Yu, Kelsey A. Dyez, Heinz Wanner, Christoph Nehrbass-Ahles, Max D. Holloway, Alan C. Mix, Valérie Masson-Delmotte, Qing Yan, Paul Gierz, Bjørg Risebrobakken, Anne-Laure Daniau, Victor Brovkin, Erin L McClymont, Michal Kucera, Patricio A. Velasquez Alvárez, Daniele Colombaroli, Christoph C. Raible, Emilie Capron, Juan Antonio Ballesteros-Cánovas, Michael Sarnthein, Julia Gottschalk, Hubertus Fischer, Liping Zhou, Jennifer R. Marlon, Julien Emile-Geay, Olga V. Churakova (Sidorova), Marie-France Loutre, Brian F. Cumming, Daniel J. Lunt, Philippe Martinez, Jennifer Saleem Arrigo, Sherilyn C. Fritz, Thomas F. Stocker, Hendrik Vogel, Fortunat Joos, Pepijn Johannes Bakker, Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern]-Universität Bern [Bern], Oeschger Centre for Climate Change Research (OCCR), University of Bern, Climate Change Research Centre [Sydney] (CCRC), University of New South Wales [Sydney] (UNSW), College of Earth, Ocean and Atmospheric Sciences [Corvallis] (CEOAS), Oregon State University (OSU), Australian National University (ANU), Bullard Laboratories, University of Cambridge [UK] (CAM), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Centre for Ice and Climate [Copenhagen], Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Center for Marine Environmental Sciences [Bremen] (MARUM), Universität Bremen, University of Toronto, Department of Geography (UNIVERSITé DE DURHAM), Durham University, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), University of Geneva [Switzerland], Institute for the Dynamics of Environmental Processes-CNR, University of Ca’ Foscari [Venice, Italy], UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), GNS Science [Lower Hutt], GNS Science, Queen's University [Kingston, Canada], Institute of Earth Surface Dynamics [Lausanne], Université de Lausanne (UNIL), Centre de recherche sur la dynamique du système Terre (GEOTOP), Université de Montréal (UdeM)-McGill University = Université McGill [Montréal, Canada]-École Polytechnique de Montréal (EPM)-Concordia University [Montreal]-Université du Québec à Rimouski (UQAR)-Université du Québec à Montréal = University of Québec in Montréal (UQAM)-Université du Québec en Abitibi-Témiscamingue (UQAT), University of Southern California (USC), University of Nebraska [Lincoln], University of Nebraska System, Past Global Changes International Project Office (PAGES), Past Global Changes International Project Office, School of Geographical Sciences [Bristol], University of Bristol [Bristol], Laboratory of Wetland Ecology and Monitoring, Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, School of Forestry and Environmental Studies, Yale University [New Haven], Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Center for Atmospheric Research [Boulder] (NCAR), Uni Research Climate, Uni Research Ltd, Université Paris sciences et lettres (PSL), National Coordination Office, Washington, Institute of Geosciences [Kiel], Christian-Albrechts-Universität zu Kiel (CAU), Department of Geology, Quaternary Sciences, Lund University [Lund], Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Institute of Geography [Bern], Nansen-Zhu International Research Center (NZC), Institute of Atmospheric Physics [Beijing] (IAP), Chinese Academy of Sciences [Beijing] (CAS)-Chinese Academy of Sciences [Beijing] (CAS), Lehigh University [Bethlehem], Department of Earth Sciences [Utrecht], Utrecht University [Utrecht], Ecole Polytechnique Fédérale de Zurich, University of Peking, Peking University [Beijing], Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université de Genève = University of Geneva (UNIGE), Université de Lausanne = University of Lausanne (UNIL), École Polytechnique de Montréal (EPM)-McGill University = Université McGill [Montréal, Canada]-Université de Montréal (UdeM)-Université du Québec en Abitibi-Témiscamingue (UQAT)-Université du Québec à Rimouski (UQAR)-Concordia University [Montreal]-Université du Québec à Montréal = University of Québec in Montréal (UQAM), University of Nebraska–Lincoln, Adam Mickiewicz University in Poznań (UAM), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Stratigraphy and paleontology, Stratigraphy & paleontology, Wolff, Eric [0000-0002-5914-8531], and Apollo - University of Cambridge Repository

Subjects
010504 meteorology & atmospheric sciences, sub-01, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Earth and Planetary Sciences(all), 3705 Geology, 010502 geochemistry & geophysics, 01 natural sciences, Ice cores climate, Paleoclimatology, Ecosystem, Settore CHIM/01 - Chimica Analitica, SDG 14 - Life Below Water, 0105 earth and related environmental sciences, 13 Climate Action, geography, geography.geographical_feature_category, Global warming, 37 Earth Sciences, 3709 Physical Geography and Environmental Geoscience, Radiative forcing, 13. Climate action, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Greenhouse gas, Climatology, Polar amplification, General Earth and Planetary Sciences, Environmental science, Climate model, Ice sheet
Abstract

International audience; Over the past 3.5 million years, there have been several intervals when climate conditions were warmer than during the pre-industrial Holocene. Although past intervals of warming were forced differently than future anthropogenic change, such periods can provide insights into potential future climate impacts and ecosystem feedbacks, especially over centennial-to-millennial timescales that are often not covered by climate model simulations. Our observation-based synthesis of the understanding of past intervals with temperatures within the range of projected future warming suggests that there is a low risk of runaway greenhouse gas feedbacks for global warming of no more than 2 °C. However, substantial regional environmental impacts can occur. A global average warming of 1–2 °C with strong polar amplification has, in the past, been accompanied by significant shifts in climate zones and the spatial distribution of land and ocean ecosystems. Sustained warming at this level has also led to substantial reductions of the Greenland and Antarctic ice sheets, with sea-level increases of at least several metres on millennial timescales. Comparison of palaeo observations with climate model results suggests that, due to the lack of certain feedback processes, model-based climate projections may underestimate long-term warming in response to future radiative forcing by as much as a factor of two, and thus may also underestimate centennial-to-millennial-scale sea-level rise.

Published
2018

26. Amber inclusions from New Zealand

Author

Jacek Szwedo, Daphne E. Lee, Peter H. Kerr, Vincent Perrichot, Mark S. Harvey, Jouko Rikkinen, Uwe Kaulfuss, Ariane Busch, Mark Maraun, Dallas C. Mildenhall, Natalie Bleile, Viktor Baranov, Jennifer M. Bannister, Art Borkent, Anna Philie Kiecksee, Alexander R. Schmidt, Christina Beimforde, John G. Conran, Elina Kettunen, Leyla J. Seyfullah, Frauke Stebner, Franziska Lengeling, Jon K. Lindqvist, Michael S. Engel, Philipp Ulbrich, Elizabeth M. Kennedy, Eva-Maria Sadowski, Department of Geobiology, Georg-August-University [Göttingen], Department of Geology [Dunedin], University of Otago [Dunedin, Nouvelle-Zélande], Department of Botany, Leibniz Institute of Freshwater Ecology & Inland Fisheries, Courant Research Centre Geobiology, Australian Centre for Evolutionary Biology and Biodiversity & Sprigg, University of Adelaide, Coburg University of Applied Sciences and Arts, SNECMA Villaroche [Moissy-Cramayel], Safran Group, GNS Science [Lower Hutt], GNS Science, Invasive Animals CRC and Institute of Applied Ecology, Room 3C44, University of Canberra, Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Faculty of Biological and Environmental Sciences [Helsinki], University of Helsinki, Abteilung Geobiologie, UOO1416, Royal Society of New ZealandRoyal Society of New Zealand, DP130104314, Australian Research Grant, Georg-August-University = Georg-August-Universität Göttingen, Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Biosciences, Lichens, Helsinki Institute of Sustainability Science (HELSUS), Finnish Museum of Natural History, Viikki Plant Science Centre (ViPS), Plant Biology, Organismal and Evolutionary Biology Research Programme, and Teachers' Academy

Subjects
0106 biological sciences, 010506 paleontology, EOCENE, INSECTS, Zoology, MIDDLE MIOCENE, FOULDEN MAAR, 010603 evolutionary biology, 01 natural sciences, SOUTH-AMERICA, Genus, OTAGO, Veliidae, OLIGOCENE, Arachnida, Oribatida, Agathis australis, 1183 Plant biology, microbiology, virology, 0105 earth and related environmental sciences, biology, Prostigmata, SOOTY MOLDS, Hexapoda, Fungi, Geology, 15. Life on land, biology.organism_classification, Mycetophilidae, ARACHNIDS, Amber, Capnodiales, 1181 Ecology, evolutionary biology, Southern hemisphere, DIPTERA, Mesostigmata, HAXAPODA, TERRESTRIAL FAUNA, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract

Amber is nearly ubiquitous in lignites from Otago and Southland and cornmon throughout New Zealand; however, no amber inclusions have been reported previously. We studied amber from 22 Cretaceous to Miocene sites in southem New Zealand, recovering inclusions at three localities: Cosy Dell (late Oligocene), Roxburgh (early Miocene), and Hyde (?early Miocene). Preparation of New Zealand amber to expose inclusions for study under incident and transmitted light is challenging and time-consuming, with most samples brittle and opaque. Thus, we stabilize and clear the amber lumps using epoxy preparation under vacuum before grinding and imaging under light microscopy. To date we have recovered 63 arthropods, as weIl as plant remains, fungi, and nematodes. Arachnids include diverse mites (Mesostigmata, Oribatida, Astigmata, and Prostigmata), a variety of spiders and web remains with prey, and a pseudoscorpion. Sorne Collembola were identified as belonging to the family Entomobryidae (Entomobryomorpha). Insects include members of the families Dermestidae (Coleoptera), Mymaridae and Scelionidae (Hymenoptera), Veliidae (Heteroptera), Ceratopogonidae (Forcipomyia) and Mycetophilidae (Diptera), as well as Psocoptera, and Lepidoptera. The most abundant fungi in New Zealand amber are hyphomycetes similar to the genus Casparyotorula from European Palaeogene ambers and we discovered similar fungi growing on resin of the extant Agathis australis, the iconic New Zealand Kauri. Furthermore, specimens of the genus Metacapnodium (Capnodiales) represent the first Southem Hemisphere fossil sooty moulds; saprophytic ascomycetes with brown hyphae, often forming extensive subicula on living plant surfaces. These fungi are ubiquitous and diverse in New Zealand today. Many of these new amber fossils represent groups with an otherwise poor fossil record for the entire Southem Hemisphere. The systematic and ecological diversity of the inclusions highlights the potential of New Zealand amber for reconstructing past terres trial ecosystems of Zealandia, one of the biogeographically crucial former Gondwanan landmasses.

Published
2018

27. Variability in the foraging range of Eudyptula minor across breeding sites in central New Zealand

Author

Susan M. Waugh, Reuben Lane, Jingjing Zhang, Caroline Bost, Charles-André Bost, Timothée A. Poupart, John P. Y. Arnould, Graeme A. Taylor, Todd E. Dennis, Junichi Sugishita, Kerry-Jayne Wilson, Karyne M. Rogers, Centre for Integrative Ecology, Deakin University [Burwood], Museum of New Zealand - Te Papa Tongarewa, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), GNS Science [Lower Hutt], GNS Science, Department of Zoology, Universty of Otago (New Zealand), University of Otago [Dunedin, Nouvelle-Zélande], Department of Conservation [New Zealand], Department of Conservation, West Coast Penguin Trust [New Zealand], West Coast Penguin Trust, School of Life and Environmental Sciences [Australia], Deakin University, and Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)

Subjects
0106 biological sciences, Eudyptula minor, Reproductive success, biology, Range (biology), Ecology, 010604 marine biology & hydrobiology, Foraging, Conservation, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, foraging range, Population variability, GPS tracking, [SDE]Environmental Sciences, Period (geology), population variability, little penguin, Animal Science and Zoology, 14. Life underwater, isotopes, Trophic level
Abstract

International audience; The little penguin Eudyptula minor is primarily an inshore forager with its range generally limited to c. 30 km of breeding sites during the nesting period. However, exceptions with greater foraging distances have been recorded in Australia. To investigate the foraging range plasticity in New Zealand we used GPS tracks gathered on 68 individuals in three regions of central New Zealand between 2011 and 2016. Foraging patterns varied between sites and between years. Tracks revealed that penguins can rely on distant foraging areas while incubating, with nesting birds travelling up to 214 km to feed. Isotope analyses of blood samples showed that this distant food across deep waters (0–200 m) is likely to be squid dominated. During the chick rearing period, birds undertook a diet shift to a higher trophic level while foraging closer to their colony, and possibly near river plumes. These findings highlight the need to consider the little penguins’ large potential foraging ranges when managing threats and changes to the environment.

Published
2017

28. Petrophysical, Geochemical, and Hydrological Evidence for Extensive Fracture-Mediated Fluid and Heat Transport in the Alpine Fault's Hanging-Wall Damage Zone

Author

M Zimmer, T Wiersberg, K Weaver, R Valdez, H Tobin, D Teagle, S Taylor-Offord, N Shigematsu, A Schleicher, Martha Savage, K Sauer, DJ Prior, J Paris, O Nitsch, O Nishikawa, A Niemeijer, H Mori, L Morales, J Moore, C Menzies, B Melosh, L Mathewson, E Mariani, D Mallyon, A Lukacs, T Little, W Lin, R Langridge, Y Kometani, M Kirilova, S Keys, N Kato, K Jacobs, Jamie Howarth, G Henry, A Hartog, A Gulley, J Grochowski, J Grieve, D Faulkner, JD Eccles, L Craw, SC Cox, A Coutts, A Cooper, Calum Chamberlain, B Carpenter, N Broderick, Carolyn Boulton, CM Boese, L Becroft, N Barth, LM Baratin, MJ Allen, J Williams, P Pezard, DR Schmitt, P Upton, L Remaud, L Janku-Capova, T Jeppson, J Coussens, C Massiot, B Célérier, ML Doan, VG Toy, Rupert Sutherland, John Townend, Victoria University of Wellington, University of Otago [Dunedin, Nouvelle-Zélande], Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Université Grenoble Alpes - UFR Langage, lettres et arts du spectacle, information et communication - Dpt Sciences de l'information et de la communication (UGA UFR LLASIC SIC), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Mécanique des Fluides et des Solides (IMFS), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Centre National de la Recherche Scientifique (CNRS), Institute of Mathematical, Physics and Computer Sciences (IMAPCS), Aberystwyth University, Institute of Geological and Nuclear Sciences (IGNS), Department of Geoscience, University of Wisconsin-Madison, Department of Geosciences [Pennsylvania], Pennsylvania State University (Penn State), Penn State System-Penn State System, GeoForschungsZentrum - Helmholtz-Zentrum Potsdam (GFZ), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), and Experimental rock deformation

Subjects
Topography, Damage zone, Fault zone, geophysics, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Hydrogeology, Petrophysics, Geophysics, hydrogeology, topography, Geochemistry and Petrology, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 13. Climate action, fault zone, Seismogenesis, damage zone, seismogenesis, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology
Abstract

© 2017. American Geophysical Union. All Rights Reserved. Fault rock assemblages reflect interaction between deformation, stress, temperature, fluid, and chemical regimes on distinct spatial and temporal scales at various positions in the crust. Here we interpret measurements made in the hanging-wall of the Alpine Fault during the second stage of the Deep Fault Drilling Project (DFDP-2). We present observational evidence for extensive fracturing and high hanging-wall hydraulic conductivity (∼10−9 to 10−7 m/s, corresponding to permeability of ∼10−16 to 10−14 m2) extending several hundred meters from the fault's principal slip zone. Mud losses, gas chemistry anomalies, and petrophysical data indicate that a subset of fractures intersected by the borehole are capable of transmitting fluid volumes of several cubic meters on time scales of hours. DFDP-2 observations and other data suggest that this hydrogeologically active portion of the fault zone in the hanging-wall is several kilometers wide in the uppermost crust. This finding is consistent with numerical models of earthquake rupture and off-fault damage. We conclude that the mechanically and hydrogeologically active part of the Alpine Fault is a more dynamic and extensive feature than commonly described in models based on exhumed faults. We propose that the hydrogeologically active damage zone of the Alpine Fault and other large active faults in areas of high topographic relief can be subdivided into an inner zone in which damage is controlled principally by earthquake rupture processes and an outer zone in which damage reflects coseismic shaking, strain accumulation and release on interseismic timescales, and inherited fracturing related to exhumation.

Published
2017

29. Urbanization impact on sulfur content on groundwater revealed by the study of urban speleothem-like deposits: case study in Paris, France

Author

Edwige Pons-Branchu, Andy Phillips, André Guillerme, Philippe Branchu, Jean-Luc Michelot, Emmanuel Dumont, Eric Douville, Mathieu Fernandez, Matthieu Roy-Barman, Liliane Jean-Soro, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Eau et Environnement (IFSTTAR/GERS/EE), PRES Université Nantes Angers Le Mans (UNAM)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Histoire des technosciences en société (HT2S), Conservatoire National des Arts et Métiers [CNAM] (CNAM), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Direction Ouest (Cerema Direction Ouest), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement (Cerema), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Géochrononologie Traceurs Archéométrie (GEOTRAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochimie Des Impacts (GEDI), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-PRES Université Nantes Angers Le Mans (UNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Centre d'Etudes et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement - Equipe-projet TEAM (Cerema Equipe-projet TEAM), Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), and HESAM Université (HESAM)-HESAM Université (HESAM)

Subjects
Pollution, Paris, Environmental Engineering, Gypsum, 010504 meteorology & atmospheric sciences, Water table, media_common.quotation_subject, Geochemistry, Speleothem, Aqueduct, 010501 environmental sciences, engineering.material, 01 natural sciences, Panoply, [SHS.HISPHILSO]Humanities and Social Sciences/History, Philosophy and Sociology of Sciences, chemistry.chemical_compound, δ34S, Urbanization, 11. Sustainability, Environmental Chemistry, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Waste Management and Disposal, Groundwater, 0105 earth and related environmental sciences, media_common, Hydrology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, 6. Clean water, Speleothems, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], engineering, Carbonate, France, Water Pollutants, Chemical, Geology, Sulfur, Environmental Monitoring
Abstract

International audience; Speleothem-like deposits that develop underground in urban areas are an archive of the environmental impact of anthropic activities that has been little studied so far. In this paper, the sulfate content in shallow groundwater from northern Paris (France) is compared with the sulfur content in two 300-year-old urban carbonate deposits that grew in a historical underground aqueduct. The present-day waters of the aqueduct have very high sulfur and calcium contents, suggesting pollution from gypsum dissolution. However, geological gypsum levels are located below the water table. Sulfur content was measured by micro-X-ray fluorescence in these very S-rich carbonate deposits (0.5 to 1% of S). A twofold S increase during the second half of the 1800s was found in both samples. These dates correspond to two major periods of urbanization above the site. We discus three possible S sources: anthropic sources (industries, fertilizers…), volcanic eruptions and input within the water through gypsum brought for urbanization above the studied site (backfill with quarry waste) since the middle of the 19th century. For the younger second half of the studied section, S input from gypsum brought during urbanization was confirmed by the study of isotopic sulfur composition (δ34S = + 15.2‰ at the top). For the oldest part, several sulfur peaks could be related to early industrial activity in Paris, that caused high local air pollution, as reported in historical archives but also to historical gypsum extraction. This study provides information on the origin and timing of the very high SO42 − levels measured nowadays within the shallow groundwater, thus demonstrating the interest in using carbonate deposits in urban areas as a proxy for the history of urbanization or human activities and their impact on water bodies.

Published
2017

30. Feeding patterns of two sympatric shark predators in coastal ecosystems of an oceanic island

Author

Sébastien Jaquemet, Clément Trystram, Marc Soria, Karyne M. Rogers, Ecologie marine tropicale dans les Océans Pacifique et Indien (ENTROPIE [Réunion]), Institut de Recherche pour le Développement (IRD)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecologie Marine (ECOMAR), Université de La Réunion (UR), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Institut de Recherche pour le Développement (IRD), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD)

Subjects
0106 biological sciences, food.ingredient, Tiger, Ecology, 010604 marine biology & hydrobiology, δ15N, Aquatic Science, Biology, Galeocerdo, 010603 evolutionary biology, 01 natural sciences, Predation, Fishery, food, Sympatric speciation, Ecosystem, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Ecology, Evolution, Behavior and Systematics, Trophic level, Apex predator
Abstract

Stomach contents and stable carbon and nitrogen isotope analyses (δ13C and δ15N) were used to investigate the trophic ecology of two apex predators, tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas), from Reunion Island to describe their dietary habits at both the population and individual levels. In this oceanic island, the tiger and bull sharks were more piscivorous and teutophagous than noted in previous research from other localities. The δ13C values suggested that bull sharks depended on more neritic organic matter sources than tiger sharks, confirming a coastal habitat preference for bull sharks. Moreover, the total length of the bull shark influenced δ13C values, with smaller individuals being more coastal than larger individuals. All indicators suggest that there is a higher degree of similarity between individual tiger sharks compared with the more heterogeneous bull shark population, which is composed of individuals who specialize on different prey. These results suggest that the two species have different functions in these coastal habitats, and thus, they must be considered independently in terms of conservation and management.

Published
2016

31. Effects of a regional décollement level for gravity tectonics on late Neogene to recent large-scale slope in the Foz do Amazonas basin, Brazil

Author

Sébastien Migeon, Carlos A. Silva, Christian Gorini, I. King, Rodrigo Perovano, Alberto Cruz, François Bache, Érika Ferreira da Silva Araújo, Laurence Droz, Antonio Tadeu dos Reis, Dept. de Oceanografia Geológica, Universidade do Estado do Rio de Janeiro [Rio de Janeiro] (UERJ), Departatmento de Geologia-Lagemar, Universidade Federal Fluminense [Rio de Janeiro] (UFF), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Directorate of Hydrography and Navigation ((DHN)), GNS Science [Lower Hutt], GNS Science, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)

Subjects
Horizon (geology), 010504 meteorology & atmospheric sciences, Stratigraphy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Context (language use), Structural basin, Late Miocene, 010502 geochemistry & geophysics, Oceanography, Neogene, 01 natural sciences, Paleontology, Tectonics, Geophysics, Subaerial, Economic Geology, Sedimentary rock, 0105 earth and related environmental sciences
Abstract

International audience; Extra sets of 2D multi-channel seismic and chronostratigraphic data allowed us to undertake analyses of source to sink processes and triggering mechanisms of the gigantic megaslides previously documented off the NW and SE steep slope settings of the Foz do Amazonas basin. As these megaslides comprise two sets of stacked allochthonous masses within the Upper Miocene-Quaternary sedimentary record, they are now described as Mass-Transport Complexes (MTCs) and have been renamed the Amapá Megaslide Complex (AMC) and the Pará-Maranhão Megaslide Complex (PMMC). Individual megaslides of both MTCs can mobilize up to kilometre-thick sedimentary series as allochthonous masses with distinct flow directions, degrees of sediment disruption and internal coherence. Megaslides spread downslope over areas as large as thousands of km2, attaining dimensions comparable to the world's largest mass-transport deposits. Among all the megaslides, the basal and largest AM1 megaslide (AMC) stands as a quite unique example of mass-transport deposit in the basin, interpreted as a dominant carbonate allochthonous mass sourced from a mixed carbonate-siliciclastic platform. The instability was probably triggered between the late Miocene and the end of the Early Pliocene by the gravitational collapse of the mixed platform under its own weight, after successive subaerial exposures which generated karstification processes. Siliciclastic-type megaslides, on the other hand, are all sourced from large upslope slide and/or rotated blocks (up to 60 km wide in the case of the PMMC). The detachment of upslope blocks was triggered by structurally-induced seabed movements during the Mid Pliocene-Pleistocene (in the case of the PMMC) and during the Pleistocene (in the case of the AMC). All mapped features support the interpretation of sedimentary blocks which have undergone long lasting deformation, having been variably folded and faulted by the sliding along an overpressured condensed section (H3 horizon). H3 horizon equally acts as the upper décollement level for the gravity tectonic system that operates on the regional scale of the Foz do Amazonas basin. In such a context, the results of this study evidence complex links between variable modes and scales of gravity processes (gravity tectonics and MTCs emplacements), all induced by instability created from a condensed section prone to produce pore fluid overpressure. And yet, seismic attributes of the décollement H3 across the slope, characterized by a reflector of negative polarity of high amplitude, indicate that the potential for similar large scale sediment failures continues to exist across the AMC and PMMC.

Published
2016

32. Accurate quantification of sediment conveyance following the 2016 Kaikoura earthquake, New Zealand

Author

Katie Jones, Jamie Howarth, Chris Massey, Pascal Sirguey, Dimitri Lague, Thomas Bernard, GNS Science, Victoria University of Wellington, University of Otago [Dunedin, Nouvelle-Zélande], Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and European Geosciences Union

Subjects
[SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology
Abstract

Evaluating the influence of earthquakes on erosion, landscape evolution and sediment-related hazards requires quantifying the volume and velocity of post-seismic sediment cascades. However, accurate estimates of post-earthquake sediment transfers remain rare. Following the 2016 MW7.8 Kaikōura earthquake in New Zealand, the volume of post-seismic erosion was quantified directly by measuring the ground surface change between 4 lidar surveys captured in 2016, 2017, 2019 and 2021 using the multiscale model-to-model cloud comparison (M3C2) algorithm. The lidar surveys covered the 62 km2 Hapuku and 66 km2 Kowhai river catchments within the Seaward Kaikōura Range, representing the two catchments with the highest density of co-seismic landsliding.The total co-seismic landslide source volume for the Hapuku Catchment was 30 ± 6 M m3,the catchment being dominated by a 17 M m3 rock avalanche which dammed the Hapuku River. In the 5 years after the earthquake a total of 10.60 ± 0.22 M m3 of sediment was post-seismically eroded (equivalent to ~26% of the co-seismic landslide debris volume when considering bulking of the landslide deposit). A total of 9.71 ± 0.23 M m3 of sediment was delivered to the riverbed resulting in considerable riverbed aggradation and 3.58 ± 0.28 M m3 was inferred to have been transported beyond the rangefront of the Seaward Kaikōura Range (equivalent to ~9% of the co-seismic landslide debris). The total co-seismic landslide source volume for the Kowhai Catchment was only 13 +4/-3 M m3. Over the 5 years 2.02 ± 0.10 M m3 of sediment was post-seismically eroded, equal to ~13% of the co-seismic landslide debris volume within the catchment. The volume delivered to the riverbed, 1.29 ± 0.10 M m3 and 0.85 ± 0.13 M m3 is presumed to have been transported beyond the rangefront (equivalent to ~5% of the co-seismic landslide debris).From these volumes, the rates at which the co-seismic landslide sediment was eroded from hillslopes, delivered off-slope to channels and exported from the range front were calculated. When projected, these rates of sediment conveyance suggest the volume of co-seismically generated sediment is likely to be evacuated from the rangefront within or close to the recurrence interval for ground motions equivalent to the Kaikōura earthquake. The Hapuku and Kowhai river catchments being examples of where co-seismic landsliding counterbalanced uplift.

Published
2023

33. Kinematics of the Kahramanmaraş triple junction: evidence of shear partitioning

Author

Özbey, Volkan, Şengör, A. M. Celâl, Henry, Pierre, Özeren, M. Sinan, Klein, Elliot, Haines, A. John, Tari, Ergin, Zabci, Cengiz, Chousianitis, Konstantinos, Güvercin, Sezim, Öğretmen, Nazik, Istanbul Technical University, Department of Geomatics Engineering, 34469, Maslak, Istanbul, Turkey, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Istanbul Technical University, Department of Geology, 34469, Maslak, Istanbul, Turkey, Eurasian Institute of Earth Sciences, Istanbul Technical University (ITU), FM Global Research, Research Division, Norwood, MA, United States, GNS Science - Institute of Geological and Nuclear Sciences, (emeritus), New Zealand, Institute of Geodynamics, National Observatory of Athens, Lofos Nymfon, Athens, Greece, Yıldız Technical University, Department of Geomatics Engineering, 34349, I ̇stanbul, Turkey, and Istanbul Technical University Scientific Research Projects Coordination Unit as MGA-2020-42584 IDTUBITAK 2214A International Research Scholarship duringPh.D. for Ph.D. candidates program with the project number 1059B142000638.

Subjects
Cyprus Arc, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, Kinematic Modeling, East Anatolian Fault, Deformation in plate boundary zones, Kahramanmaraş triple junction
Abstract

We present an up-to-date velocity field around the north of the eastern Mediterranean, southern Turkey, Cyprus, Levant, and East Anatolian faults therein and discuss its tectonic implications. We perform a block model inversion to calculate rigid block motion, slip rates on the dislocation sources along block boundaries. Our best fitting model locates the Sinai-Anatolia Euler pole at 32.04±1.8° N, 38.21±2.4° E with a 0.596±0.084 clockwise rotation rate. Convergence rate on the Cyprus arc is $\sim$3-6 mm/yr, progressively decreasing from west to east. Kyrenia range has a left lateral slip behavior with a 3-4 mm/yr rate. We thus show that there is shear partitioning between the Cyprus subduction and Kyrenia fault zone. The northeast prolongation of the Kyrenia fault east of the Adana basin accommodates extensional and strike-slip motion, which is consistent with focal mechanisms. Further East, the relative strike-slip motion between Arabia and Anatolia is partitioned between the East Anatolian Fault (slip rates 5-6 mm/yr) and the \c{C}ardak and Malatya faults (slip rates 1.7-1.8 mm/yr), and also causes distributed deformation between these two fault systems. The Levant fault has a 3.2-4.0 mm/yr left-lateral slip rate, decreasing northward. A continuum kinematic model shows a compressional to transpressional strain accumulation across the Cyprus arc that is also compatible with its progressive change of orientation. The largest values for the second invariant of strain rate tensor define a region from Hatay to Malatya corresponding to a 50-60 km wide East Anatolian shear zone. The whole area north of the Kahramanmara{{\c{s}}} triple junction appear to be under E-W extension. Strain rates appear relatively small in the Taurus and vary from extensional to compressional along the mountain range.

Published
2023

34. Olivine in the Udachnaya-East Kimberlite (Yakutia, Russia): Types, Compositions and Origins

Author

Alexander V. Golovin, Maya B. Kamenetsky, Vadim S. Kamenetsky, Kevin Faure, D. V. Kuzmin, Sylvie Demouchy, Alexander V. Sobolev, Victor V. Sharygin, ARC Centre of Excellence in Ore Deposits (CODES), University of Tasmania [Hobart, Australia] (UTAS), School of Earth Sciences [Hobart], Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, Vernadsky Institute of Geochemistry and Analytical Chemistry (GEOKHI), Russian Academy of Sciences [Moscow] (RAS), Sobolev Institute of Geology and Mineralogy [Novosibirsk], Siberian Branch of the Russian Academy of Sciences (SB RAS), University of Minnesota [Twin Cities] (UMN), University of Minnesota System, GNS Science [Lower Hutt], and GNS Science

Subjects
Basalt, Olivine, kimberlite, 010504 meteorology & atmospheric sciences, oxygen isotopes, partial melting, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, Partial melting, Geochemistry, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), carbonatitic melt, Geophysics, Geochemistry and Petrology, Ultramafic rock, Carbonatite, engineering, H2O, olivine, Kimberlite, Geology, 0105 earth and related environmental sciences, Melt inclusions
Abstract

Olivine is the principal mineral of kimberlite magmas, and is the main contributor to the ultramafic composition of kimberlite rocks. Olivine is partly or completely altered in common kimberlites, and thus unavailable for studies of the origin and evolution of kimberlite magmas. The masking effects of alteration, common in kimberlites worldwide, are overcome in this study of the exceptionally fresh diamondiferous kimberlites of the Udachnaya-East pipe from the DaldynAlakit province, Yakutia, northern Siberia. These serpentine-free kimberlites contain large amounts of olivine (similar to 50 vol.%) in a chloridecarbonate groundmass. Olivine is represented by two populations (olivine-I and groundmass olivine-II) differing in morphology, colour and grain size, and trapped mineral and melt inclusions. The large fragmental olivine-I is compositionally variable in terms of major (Fo(8594)) and trace element concentrations, including H2O content (10-136 ppm). Multiple sources of olivine-I, such as convecting and lithospheric mantle, are suggested. The groundmass olivine-II is recognized by smaller grain sizes and perfect crystallographic shapes that indicate crystallization during magma ascent and emplacement. However, a simple crystallization history for olivine-II is complicated by complex zoning in terms of Fo values and trace element contents. The cores of olivine-II are compositionally similar to olivine-I, which suggests a genetic link between these two types of olivine. Olivine-I and olivine-II have oxygen isotope values ( +5.6+/- 0.1 parts per thousand VSMOW, 1 SD) that are indistinguishable from one another, but higher than values (+5.18 +/- 0.28 parts per thousand) in typical mantle olivine. These elevated values probably reflect equilibrium with the Udachnaya carbonate melt at low temperatures and O-18-enriched mantle source. The volumetrically significant rims of olivine-II have constant Fo values (89.0 +/- 0.2 mol%), but variable trace element compositions. The uniform Fo compositions of the rims imply an absence of fractionation of the melts Fe2+/Mg, which is possible in the carbonatite meltolivine system. The kimberlite melt is argued to have originated in the mantle as a chloridecarbonate liquid, devoid of ultramafic or basaltic aluminosilicate components, but became olivine-laden and olivine-saturated by scavenging olivine crystals from the pathway rocks and dissolving them en route to the surface. During emplacement the kimberlite magma changed progressively towards an original alkali-rich chloridecarbonate melt by extensively crystallizing groundmass olivine and gravitational separation of solids in the pipe.

Published
2007

35. Messinian evaporite deposition during sea level rise in the Gulf of Lions (Western Mediterranean)

Author

Christian Gorini, Daniel Aslanian, François Bache, Jean-Pierre Suc, Damien Do Couto, Antonio Tadeu dos Reis, Marina Rabineau, Jean-Loup Rubino, Estelle Leroux, Gwenaël Jouannic, Jean-Louis Olivet, Georges Clauzon, Speranta Maria Popescu, Julien Gargani, GNS Science [Lower Hutt], GNS Science, Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géodynamique et Géophysique (LGG), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Centre scientifique et Technique Jean Feger (CSTJF), TOTAL FINA ELF, Departamento de Oceanografia Geologica, Universidade do Estado do Rio de Janeiro [Rio de Janeiro] (UERJ), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), TOTAL-Scientific and Technical Center Jean Féger (CSTJF), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), GeoBioStratData.Consulting, TOTAL S.A., Centre d'études techniques de l'équipement Est (CETE Est), Avant création Cerema, Departamento de Oceanografia Geológica - Faculdade de Oceanografia, Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), and Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Mediterranean climate, Evaporite, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Stratigraphy, Evaporites, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Structural basin, Mediterranean, Oceanography, Deposition (geology), Paleontology, Mediterranean sea, Messinian, 14. Life underwater, Shore, geography, geography.geographical_feature_category, Continental shelf, Geology, Geophysics, 13. Climate action, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Subaerial, Gulf of Lions, Economic Geology, Seismic stratigraphy
Abstract

International audience; The Messinian Salinity Crisis resulted from desiccation of the Mediterranean Sea after its isolation from the Atlantic Ocean at the end of the Miocene. Stratal geometry tied to borehole data in the Gulf of Lions show that the pre-crisis continental shelf has been eroded during a major sea-level fall and that sedi-ments from this erosion have been deposited in the basin. This detrital package is onlapped by high amplitude seismic reflectors overlain by the "Messinian Salt" and the "Upper Evaporites". Towards the shelf, the transition between regressive deposits and overlying onlapping sediments is characterised by a wave-ravinement surface, suggesting that a significant part of the onlapping reflectors and overlying Messinian Evaporites were deposited during a relatively slow landward migration of the shoreline. The clear boundary between the smooth wave-ravinement surface and the subaerial Messinian Erosional Surface observed on the Gulf of Lions shelf and onshore in the Rh^ one valley is interpreted to have resulted from a rapid acceleration of the Mediterranean sea level rise at the end of the Messinian Salinity Crisis. Numerical simulation of this cycle of sea level change during the Messinian Salinity Crisis and of precipitation of thick evaporites during the slow sea level rise shows that this scenario can be modelled assuming a value of evaporation minus precipitation of 1.75 m 3 /m 2 /yr in the deep Mediterranean basins.

Published
2015

36. High-resolution magnetics reveal the deep structure of a volcanic-arc-related basalt-hosted hydrothermal site (Palinuro, Tyrrhenian Sea)

Author

Szitkar, Florent, Petersen, Sven, Caratori Tontini, Fabio, Cocchi, Luca, Geological Survey of Norway (NGU), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), GNS Science [Lower Hutt], GNS Science, Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Roma (INGV), and Istituto Nazionale di Geofisica e Vulcanologia

Subjects
magnetic anomalies, hydrothermalism, volcanic arcs, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]
Abstract

International audience; High-resolution magnetic surveys have been acquired over the partially sedimented Palinuro massive sulfide deposits in the Aeolian volcanic arc, Tyrrhenian Sea. Surveys flown close to the seafloor using an autonomous underwater vehicle (AUV) show that the volcanic-arc-related basalt-hosted hydrothermal site is associated with zones of lower magnetization. This observation reflects the alteration of basalt affected by hydrothermal circulation and/or the progressive accumulation of a nonmagnetic deposit made of hydrothermal and volcaniclastic material and/or a thermal demagnetization of titanomagnetite due to the upwelling of hot fluids. To discriminate among these inferences, estimate the shape of the nonmagnetic deposit and the characteristics of the underlying altered area-the stockwork-we use high-resolution vector magnetic data acquired by the AUV Abyss (GEOMAR) above a crater-shaped depression hosting a weakly active hydrothermal site. Our study unveils a relatively small nonmagnetic deposit accumulated at the bottom of the depression and locked between the surrounding volcanic cones. Thermal demagnetization is unlikely but the stockwork extends beyond the limits of the nonmagnetic deposit, forming lobe-shaped zones believed to be a consequence of older volcanic episodes having contributed in generating the cones.

Published
2015

37. Seismic stratigraphy and paleogeographic evolution of Fairway Basin, Northern Zealandia, Southwest Pacific: from Cretaceous Gondwana breakup to Cenozoic Tonga–Kermadec subduction

Author

Pierrick Rouillard, François Bache, Pierre Maurizot, Martin Patriat, Rupert Sutherland, Samuel Etienne, Julien Collot, ZoNeCo Research Program, Nouméa, Service de la Géologie de Nouvelle Calédonie, Direction de l'Industrie, des Mines et de l'Energie de Nouvelle Calédonie, GNS Science [Lower Hutt], GNS Science, Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Pôle de recherche pour l'organisation et la diffusion de l'information géographique (PRODIG), Université Paris 1 Panthéon-Sorbonne (UP1)-Institut de Recherche pour le Développement (IRD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris-Sorbonne (UP4)-AgroParisTech-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)

Subjects
010504 meteorology & atmospheric sciences, stratigraphie sismique, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Structural basin, Fairway, 010502 geochemistry & geophysics, 01 natural sciences, Unconformity, [SHS]Humanities and Social Sciences, Paleontology, bassin, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Rift, Subduction, Terrigenous sediment, Geology, [SHS.GEO]Humanities and Social Sciences/Geography, 15. Life on land, Cretaceous, Gondwana, Plate tectonics, 13. Climate action, [SDU]Sciences of the Universe [physics], [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Zealandia, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, évolution paléogéographique
Abstract

We present the first comprehensive seismic‐stratigraphic analysis of Fairway Basin, which is situated on the rifted continent of Zealandia in the Tasman Sea, southwest Pacific, between Australia and New Caledonia. The basin is 700 km long, 150 km wide, and has water depths of 500–3000 m. We describe depositional architecture and paleogeographic evolution of this basin. Basin formation was concurrent with two tectonic events: (i) Cretaceous rifting during eastern Gondwana breakup and (ii) initiation and Cenozoic evolution of Tonga–Kermadec subduction system to the east of the basin. To interpret the basin history we compiled and interpreted 2D seismic‐reflection profiles and make correlations with DSDP boreholes and the geology of New Caledonia. Five seismic‐stratigraphic units were defined. The deepest and oldest unit, FW3, folded and faulted can be correlated with volcaniclastic sediments and magmatic rocks in New Caledonia that are associated with Mesozoic Gondwana margin subduction. Alternatively, given the basin location 200–300 km west of New Caledonia and inboard of the ancient plate boundary, the unit could have formed as Gondwana intra‐continental basin with no known correlative. The overlying unit FW2b records syn‐rift deposition, probably associated with Cretaceous Gondwana breakup. Subaerial erosion supplied terrigenous sediment into the deltas in the northern part of the basin, as suggested by the truncation surfaces on the basement highs and sigmoid reflector geometries within unit FW2b respectively. Above, unit FW2a records post‐rift sedimentation and passive subsidence as the Tasman Sea opened and the Fairway Basin drifted away from Australia. Subsidence led to the flooding of the basement highs and burial of wave‐cut surfaces. Eocene compressive deformation resulted in minor folding and tilting within the Fairway Basin and was associated with the formation of many diapiric structures. The top of unit FW2 is an extensive unconformity that is associated with erosion and truncation on surrounding ridges. Above this unconformity, unit FW1b is interpreted as a turbidite system sourced from topography created during the Eocene tectonic event, which we interpret as being related to Tonga–Kermadec subduction initiation. Pelagic carbonate sedimentation is now prevalent. Unit FW1a has progressively draped the basin during Oligocene to Pleistocene subsidence. Many small volcanic cones were erupted during this final phase of subsidence, either as a delayed consequence of subduction initiation, or related to Tasmantid and Lord Howe hotspot trails. The northern Fairway Ridge remains close to sea level and its reef system continues to supply carbonate detrital sediments into the basin, most likely during sea‐level lowstands. Fairway Basin contains a nearly continuous record of tectonic and paleoclimatic events in the southwest Pacific since Cretaceous time. Its paleogeographic history is a key piece in the puzzle for understanding patterns of regional biodiversity in the southwest Pacific.

Published
2015

38. Quantification des flux sédimentairesdétritiques et de la subsidence du bassinprovencal depuis 23 Ma

Author

Leroux, Estelle, Rabineau, Marina, Aslanian, Daniel, Gorini, Christian, Bache, François, Molliex, Stéphane, Robin, Cecile, Al., Et, Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), and Dubigeon, Isabelle

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

National audience; Bien que le Golfe du Lion et le Bassin Provençal aient été l’objet derecherche intensive à toute échelle de temps et d’espace, les budgetssédimentaires et les mouvements verticaux depuis la formation de lamarge demeuraient mal contraints ou sources de controverses. Ils sontici quantifiés à partir de l’interprétation de nombreux profils sismiques,d’après les concepts de stratigraphie sismique et séquentielle [Vail et al.,1977], complétée par des données de forages et de sismique réfraction,et validée par des modélisations stratigraphiques avec Dionisos [Granjeon& Joseph, 1999]. La continuité stratigraphique entre le domainede plate-forme et le bassin profond établie, la vision complète du remplissagesédimentaire de la marge permet de déceler une augmentationtrès forte (X2) des apports détritiques autour de 1 Ma en liaison avec leschangements climatiques de la révolution Mi-Pléistocène et le changementde fréquence et d’amplitude des cycles eustatiques. L’accélérationmondiale (par 3) des flux terrigènes il y a 5 Ma, défendue par de nombreuxauteurs et corrélée aux grandes orogénèses (ici alpine), est égalementobservée dans notre bassin. L’enregistrement sédimentaire fourniten outre de précieux indicateurs des mouvements verticaux de la margedepuis le rifting (Rabineau et al., 2014). Les trois domaines de subsidencedifférentielle mis en évidence se corrèlent en effet aux grandsdomaines structuraux sous-jacents identifiés grâce aux données de sismiquegrand angle (Aslanian et al., 2012, Moulin et al., soumis) : (1) le domaine à croûte continentale, (2) celui à croûte continentale amincieet (3) celui à croûte intermédiaire

Published
2014

39. Eocene and Oligocene basins and ridges of the Coral Sea-New Caledonia region: Tectonic link between Melanesia, Fiji, and Zealandia

Author

Nick Mortimer, Phillip B. Gans, Michel Monzier, Richard H. Herzer, J. Michael Palin, Bernard Pelletier, GNS Science [Lower Hutt], GNS Science, Department of Geological Sciences [Santa Barbara], University of California [Santa Barbara] (UCSB), University of California-University of California, University of Otago [Dunedin, Nouvelle-Zélande], Institut de Recherche pour le Développement (IRD [Nouvelle-Calédonie]), Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Subduction, Trough (geology), [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Guyot, Structural basin, 010502 geochemistry & geophysics, Ophiolite, 01 natural sciences, Igneous rock, Paleontology, Geophysics, Geochemistry and Petrology, Ridge, Back-arc basin, 14. Life underwater, Geology, 0105 earth and related environmental sciences
Abstract

International audience; This paper presents 34 geochemical analyses, 24 Ar‐Ar ages, and two U‐Pb ages of igneous rocks from the back‐arc basins and submarine ridges in the Coral Sea‐New Caledonia region. The D'Entrecasteaux Ridge is a composite structural feature. Primitive arc tholeiites of Eocene age (34–56 Ma) are present along a 200 km length of the ridge and arguably were part of the initial line of subduction inception between Fiji and the Marianas; substantial Eocene arc edifices are only evident at the eastern end where Bougainville Guyot andesite breccias are dated at 40 ± 2 Ma. The South Rennell Trough is confidently identified as a 28–29 Ma (early Oligocene) fossil spreading ridge, and hence, the flanking Santa Cruz and D'Entrecasteaux basins belong in the group of SW Pacific Eocene‐Early Miocene back‐arc basins that include the Solomon Sea, North Loyalty, and South Fiji basins. The rate and duration of spreading in the North Loyalty Basin is revised to 43 mm/yr between 28 and 44 Ma, longer and faster than previously recognized. The direction of its opening was to the southeast, that is, parallel to the continent‐ocean boundary and perpendicular to the direction of coeval New Caledonia ophiolite emplacement. Medium‐ and high‐K alkaline lavas of 23–25 Ma (late Oligocene) age on the northern Norfolk Ridge are an additional magmatic response to Pacific trench rollback.

Published
2014

40. Quantifying subsidence and isostatic readjustment using sedimentary paleomarkers, example from the Gulf of Lion

Author

Jean-Loup Rubino, Christian Gorini, Jean-Louis Olivet, Maryline Moulin, Stéphane Molliex, François Bache, Marina Rabineau, Estelle Leroux, Daniel Aslanian, François Guillocheau, A. T. Dos Reis, Laurence Droz, Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), GNS Science [Lower Hutt], GNS Science, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro [Rio de Janeiro] (UERJ), TOTAL S.A., TOTAL FINA ELF, Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Géosciences Marines (GM), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, isostasy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Structural basin, 010502 geochemistry & geophysics, 01 natural sciences, Thermal subsidence, Geochemistry and Petrology, Passive margin, Earth and Planetary Sciences (miscellaneous), Mediterranean Sea, 14. Life underwater, pliocene-quaternary, Geomorphology, Gulf of Lion, 0105 earth and related environmental sciences, subsidence, Canyon, geography, geography.geographical_feature_category, Subsidence (atmosphere), Post-glacial rebound, Tectonics, Geophysics, 13. Climate action, Space and Planetary Science, Sedimentary rock, messinian salinity crisis, Geology
Abstract

International audience; Passive margins are characterised by an important tectonic and thermal subsidence, which favours a good preservation of sedimentary sequences. This sedimentation in turn enhances the subsidence because of loading effects. We present here a direct method based on sedimentary markers seen on seismic data, to evaluate total subsidence rates from the coast to the outer shelf and to the deep basin in the Gulf of Lion, from the beginning of massive salt deposition up to present day (the last circa 6 Ma) with minimal theoretical assumptions. On the shelf, the Pliocene-Quaternary subsidence shows a seaward tilt reaching a rate of 240 m/Ma (±15 m/Ma) at the shelf break (70 km from the present day coastline) (i.e. a total angle of rotation of 0.88° (0.16°/Ma)). We were also able to measure and quantify for the first time the isostatic rebound of the outer shelf due to the Messinian salinity crisis (MSC). This value is very high and reaches up to 1.3 km of uplift during the crisis around the Herault-Sète canyon heads (around 1.8 km/Ma). On the slope, we also find a seaward tilting subsidence from Km 90 to Km 180 with a measured angle of 1.41°. From 180 km to the deepest part of the basin, the total subsidence is then almost vertical and reaches 960 m/Ma (±40 m/Ma) during the last 5.7 Ma (±0.25 Ma) in the deepest part of the basin. The subsidence is organised in three compartments that seem related to the very deep structure of the margin during the opening of the Liguro-provencal basin. These very high total subsidence rates enable high sedimentation rates along the margin with sediments provided by the Rhône river flowing from the Alps, which in turn enable the detailed record of climate evolution during Pliocene-Quaternary that make of the Gulf of Lion a unique archive.

Published
2014

41. Not all calcite ballast is created equal: differing effects of foraminiferan and coccolith calcite on the formation and sinking of aggregates

Author

Morgane Gallinari, K. Schmidt, C. L. De La Rocha, Giuseppe Cortese, Faculty of Mathematics and Natural Sciences, University of Groningen [Groningen], Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, European Project: 264933,EC:FP7:ENV,FP7-ENV-2010,EURO-BASIN(2010), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Ballast, 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:Life, Mineralogy, REMINERALIZATION, SEDIMENT, Deep sea, 01 natural sciences, Sink (geography), Coccolith, chemistry.chemical_compound, lcsh:QH540-549.5, PARTICLES, RATES, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Earth-Surface Processes, Marine snow, Emiliania huxleyi, ATLANTIC-OCEAN, 0105 earth and related environmental sciences, Calcite, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, biology, ACL, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, VELOCITY, biology.organism_classification, MARINE SNOW, lcsh:Geology, lcsh:QH501-531, Calcium carbonate, chemistry, EMILIANIA-HUXLEYI, lcsh:Ecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ZOOPLANKTON FECAL PELLETS, Geology
Abstract

Correlation between particulate organic carbon (POC) and calcium carbonate sinking through the deep ocean has led to the idea that ballast provided by calcium carbonate is important for the export of POC from the surface ocean. While this idea is certainly to some extent true, it is worth considering in more nuance, for example, examining the different effects on the aggregation and sinking of POC of small, non-sinking calcite particles like coccoliths and large, rapidly sinking calcite like planktonic foraminiferan tests. We have done that here in a simple experiment carried out in roller tanks that allow particles to sink continuously without being impeded by container walls. Coccoliths were efficiently incorporated into aggregates that formed during the experiment, increasing their sinking speed compared to similarly sized aggregates lacking added calcite ballast. The foraminiferan tests, which sank as fast as 700 m d−1, became associated with only very minor amounts of POC. In addition, when they collided with other, larger, foraminferan-less aggregates, they fragmented them into two smaller, more slowly sinking aggregates. While these effects were certainly exaggerated within the confines of the roller tanks, they clearly demonstrate that calcium carbonate ballast is not just calcium carbonate ballast- different forms of calcium carbonate ballast have notably different effects on POC aggregation, sinking, and export.

Published
2014

42. High temperature instruments and methods developed for supercritical geothermal reservoir characterisation and exploitation-The HiTI project

Author

Jean-Marc Naisse, Jean-Luc Deltombe, Thomas Reinsch, David Mainprice, Benoit Gibert, François Lebert, Costas Karytsas, Bernard Sanjuan, Romain Millot, Philippe Pezard, Colin Johnston, Nigel Halladay, Jan Henninges, Marie Violay, Ragnar Asmundsson, Pierre Azais, Cécile Massiot, Alain Gadalia, 4.1 Reservoir Technologies, 4.0 Chemistry and Material Cycles, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum, Iceland GeoSurvey (ISOR ), Heat Research and Development (HEAT), Transferts en milieux poreux, Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Advanced Logic Technology (ALT), Calidus Engineering Ldt, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Manteau et Interfaces, Centre for Renewable Energy Sources and Savings (CRES), CRES, Oxford Applied Technology, University of Oxford, Finanvement UE, Projet FP7 HITI, European Project: 35108,HITI, and University of Oxford [Oxford]

Subjects
Basalt experiments, 010504 meteorology & atmospheric sciences, Petroleum engineering, Renewable Energy, Sustainability and the Environment, Iceland Deep Drilling Project, [SDE.MCG]Environmental Sciences/Global Changes, Petrophysics, Geothermal reservoir, Geology, 550 - Earth sciences, 010502 geochemistry & geophysics, Geotechnical Engineering and Engineering Geology, High temperature, 01 natural sciences, Supercritical fluid, Downhole, Temperature and pressure, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Supercritical, Geothermometers, Televiewer, 0105 earth and related environmental sciences
Abstract

During the early years of the Iceland Deep Drilling Project (IDDP), development of three distinctive technological and scientific approaches were formalised and then carried out until 2010 within a European funded project called HiTI (high temperature instruments for supercritical geothermal reservoir characterisation and exploitation). These approaches were: (1) development of several downhole instruments allowing them to function up to 300 °C and 400 °C, (2) identification of two new Na/Li cation ratio geothermometric relationships valid at very high temperature, (3) tracer testing with high temperature tolerant organic isomers and finally and (4) basalt rock deformation and petrophysical properties laboratory investigations at high temperature and pressure conditions. © 2013 Elsevier Ltd. All rights reserved.

Published
2014

43. Foulden Maar and South Island amber (New Zealand) - two exceptional windows into Southern Hemisphere Cenozoic terrestrial ecosystems

Author

Kaulfuss, Uwe, Lee, Daphne, Bannister, Jennifer, Lindqvist, John, Conran, John, Mildenhall, Dallas, Kennedy, Elizabeth, Perrichot, Vincent, Maraun, Mark, Schmidt, Alexander-R., Department of Geology [Dunedin], University of Otago [Dunedin, Nouvelle-Zélande], Department of Botany, Australian Centre for Evolutionary Biology and Biodiversity & Sprigg, University of Adelaide, GNS Science [Lower Hutt], GNS Science, Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Courant Research Centre Geobiology, Georg-August-University [Göttingen], Joachim Reitner, Yang Qun, Wang Yongdong and Mike Reich (Eds.), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), and Georg-August-University = Georg-August-Universität Göttingen

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; Foulden Maar, Otago, New Zealand, is an Early Miocene maar-diatreme volcano with a crater filled by highly fossiliferous lacustrine diatomite. Since investigations began in late 2003, several thousand exquisitely preserved macro- and microfossils have been collected from plants and animals that lived in or around the maar-lake. The flora includes ferns, leaves with cuticle, flowers with pollen, fruits, seeds and wood, which, together with pollen data, are indicative of a diverse subtropical Lauraceae-dominated rainforest growing on volcanic soils around the lake. Diverse, mainly ground-dwelling insects and spiders from eight orders and arthropod- plant interactions show that arthropods were a key component of the forest ecosystem. Aquatic taxa include fish, diatoms, sponges, Chrysophyceae, a few water plants and insects. The majority of arthropods from Foulden Maar have close representatives in the modern fauna, but many of the plant taxa are now extinct in New Zealand. Together, these fossils provide an unrivalled opportunity to reconstruct a well-dated Southern Hemisphere, mid-latitude, earliest Miocene lacustrine/forest ecosystem. Recently, amber from the South Island, New Zealand has become an exceptional novel paleontological source for terrestrial microorganisms and arthropods with an otherwise poor fossil record. Amber is nearly ubiquitous in coal/lignite and non-carbonaceous sediments throughout the South Island but no animal inclusions and only a few floral remains have been recognised until now. In an ongoing study, we have collected amber from the Upper Cretaceous, Eocene, Oligocene, Miocene and Pliocene, including discrete blocks, rounded "amberpebbles", millimetre-sized drops, sometimes associated with wood, and tiny resin plugs on leaf fossils. The preliminary study of these samples has revealed a range of well-preserved inclusions, including (1), araucariacean wood, (2), fungi, (3), sheathed prokaryotic filaments, (4), arachnids such as mites, a possible tick and spiders, (5), springtails (Collembola), and (6), insects including beetles, dipterans, hymenopterans, hemipterans, and lepidopterans. These finds attest to the quality of New Zealand amber inclusions and their remarkable potential for reconstructing past terrestrial ecosystems.

Published
2013

44. Climate mediated size variability of diatom Fragilariopsis kerguelensis in the Southern Ocean

Author

Ganapati N. Nayak, Sunil Kumar Shukla, Xavier Crosta, Giuseppe Cortese, Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], and GNS Science

Subjects
Polar front, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010506 paleontology, Archeology, Global and Planetary Change, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Geology, 01 natural sciences, Oceanography, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Interglacial, Sea ice, Deglaciation, Upwelling, Thermohaline circulation, 14. Life underwater, Glacial period, Ecology, Evolution, Behavior and Systematics, Holocene, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract

Fragilariopsis kerguelensis (O'Meara) Hustedt is the most abundant open ocean diatom species in Southern Ocean sediments and its average valve area has recently been used to infer glacial–interglacial paleoceanographic conditions. Studies from the Atlantic sector of the Southern Ocean demonstrated how larger average valve area of F. kerguelensis during the Last Glacial compared to the interglacial possibly relate to greater availability of iron (through wider sea ice coverage and higher eolian dust input). We present here data on average valve area of F. kerguelensis from three sediment cores covering the last ∼42 cal ka BP from different zones of the Southern Ocean. Our records confirm previous results from the Atlantic sector, but highlight a different pattern from the Indian sector where the largest valves of F. kerguelensis are encountered during the Holocene. Fragilariopsis kerguelensis average valve area variations in the Antarctic Polar Front (APF) of the Atlantic sector and Subantarctic Front of the Indian sector are in phase with records of opal burial while this correlation does not hold for the APF of the Indian sector. Variations in circum-polar upwelling were suggested as the main controlling factor of opal production during the last 20,000 years. We here hypothesize that high nutrient input from the Antarctic Peninsula during the last deglaciation may have exerted a stronger control on F. kerguelensis average valve area and opal export in the Atlantic sector of the Southern Ocean than inferred changes in circum-polar upwelling.

Published
2013

45. Quantification des flux sédimentaires détritiques et de la subsidence post-rift du bassin provençal

Author

Leroux, Estelle, Rabineau, Marina, Aslanian, Daniel, Bache, François, Molliex, Stéphane, Robin, Cécile, Droz, Laurence, Gorini, Christian, Granjeon, Didier, Moulin, Maryline, Dubigeon, Isabelle, Association des Sédimentologistes Français, Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), GNS Science [Lower Hutt], GNS Science, Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), IFP Energies nouvelles (IFPEN), Géosciences Marines (GM), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

National audience; Le bassin Provençal a fait l'objet de modélisations stratigraphiques 3D avec Dionisos [Granjeon & Joseph, 1999] à deux échelles de temps : celle du post-rift (20 Ma jusqu'à l'actuel), et celle de la crise de salinité Messinienne (5.96 Ma - 5.32 Ma). L'objectif était de tester (1) notre modèle d'évolution de la marge du Golfe du Lion (les flux sédimentaires et la subsidence avaient été préalablement quantifiés) [Leroux, 2012] et (2) le scénario de la crise de salinité Messinienne de [Bache et al., 2009], en particulier l'ampleur des dépôts détritiques issus de l'érosion et du démantèlement de la marge, ainsi que la remontée du niveau marin en 2 temps [Bache et al., 2012]. Ces modélisations nous ont permis de valider (1) notre modèle d'évolution de la marge depuis 20 Ma et (2) le scénario de la crise messinienne. Ces modélisations nécessitent toutefois d'être précisées notamment en terme de réajustements isostatiques liés à la crise de salinité. La modélisation de la totalité du remplissage sédimentaire (incluant le syn-rift) est aujourd'hui envisagée dans la continuité de ce travail. Elle implique de quantifier puis d'intégrer dans Dionisios les flux sédimentaires et mouvements verticaux de la marge homologue Ouest-Sarde, ainsi que la cinématique du rifting oligo-aquitanien. Références - Granjeon, D., Joseph, P., 1999. Concepts and applications of a 3-d multiple lithology, diffusive model in stratigraphic modelling. In: Numerical Experiments in Stratigraphy: Recent Advances in Stratigraphic and Sedimentologic Computer Simulation, SEPM Spec. Pub. 62, Tulsa, 197-210. - Leroux, E., 2012. Quantification des flux sédimentaires et de la subsidence du bassin Provençal. Thèse de doctorat de l'Université de Bretagne Occidentale, Brest, 455 p. - Bache, F., Olivet, J.-L., Gorini, C., Rabineau, M., Baztan, J., Aslanian, D. and Suc J.-P., 2009. Messinian erosional and salinity crises:View from the provence basin (Gulf of Lions, western mediterranean). Earth Planet. Sci. Lett. 286, 139-157. - Bache, F., Popescu, S.M., Rabineau, M., Gorini, C., Suc, J.-P., Clauzon G., Olivet, J-L., Rubino, J-L., Melinte-Dobrinescu, M.C., Estrada, F., Londeix, L., Armijo, R., Meyer, B., Jolivet, L., Jouannic, G., Leroux, E., Aslanian, D., Baztan, J., Dos Reis, A.T., Mocochain, L., Dumurdzanov, N., Zagorchev, I., Lesic, V., Tomic, D., Cagatay, M.N., Brun, J-P., Sokoutis, D., Csato, I., Ucarkus, G., Cakir, Z., 2012. A two step process for the reflooding of the Mediterranean after the Messinian Salinity Crisis. Basin Research 23, 1-29.

Published
2013

46. Neogene evolution of lower trench-slope basins and wedge development in the central Hikurangi subduction margin, New Zealand

Author

Andrew Nicol, Geoffroy Mahieux, Julien Bailleul, Cécile Robin, Jacky Ferrière, Christian Gorini, Frank Chanier, Vincent Caron, Département Géosciences, Institut Polytechnique Lassalle-Beauvais, Géosystèmes - UMR 8217, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Laboratoire de Sédimentologie et de Géochimie, Université de Picardie Jules Verne (UPJV), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Géosystèmes, Université de Lille, Sciences et Technologies, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)

Subjects
010504 meteorology & atmospheric sciences, Stratigraphy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Structural basin, 010502 geochemistry & geophysics, Slope basins, 01 natural sciences, Paleontology, Active margin, Passive margin, Geomorphology, 0105 earth and related environmental sciences, Earth-Surface Processes, geography, Tectonic subsidence, Flysch, geography.geographical_feature_category, Subduction, Subduction wedge, 15. Life on land, Sedimentary basin, Deformation, Tectonics, Geophysics, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Sedimentary rock, Geology, New Zealand
Abstract

International audience; Detailed analysis of the stratigraphic architecture and deformation of lower trench-slope sedimentary basins permits the tectonic evolution of subduction margins to be constrained. This study utilises offshore seismic reflection profiles and onshore outcrop data to examine the entire lower trench-slope of the Hikurangi subduction margin in the eastern North Island, New Zealand. Our results constrain the main spatial and temporal changes of facies and sedimentary units since about 25 Ma. We demonstrate that the geometries and locations of Miocene to Quaternary sedimentary basins are controlled by tectonic activity and reflect stages of subduction wedge development. Four types of sedimentary basins have been recognized: 1) flysch basins with local olistostromes at the front of seaward propagating thrust sheets; 2) 5-10 km wide turbidite-rich trench-slope basins between uplifting structural ridges (i.e. anticlines) associated with shortening within 100 km of the subduction front at the seafloor; 3) 30-40 km wide trench-slope basins associated with an upslope increase in thrust and ridge spacing; and 4) mixed siliciclastic-carbonate shelves formed in association with margin uplift after filling of the wider (30-40 km) trench-slope basins. The lateral and vertical successions of basin geometries and sedimentary infill are consistent with the overall progressive uplift of the subduction wedge. Formation of some of the wide trench-slope basins may be accompanied by significant local subsidence and normal faulting synchronous with active shortening at the subduction front. Margin-wide normal faulting during the Middle-Late Miocene may have formed due to upslope collapse related to tectonic erosion. All of the basins studied contain major unconformities at their base and top, with basin strata deposited over about 2-8 Myr. The short life span of these lower trench-slope sedimentary basins is consistent with a succession of short paroxysmal tectonic episodes rather than continuous deformation for the duration of subduction. Stratigraphic discontinuities within basins (e.g., facies changes and reversal of paleo-currents) also record short-term tectonic events (c. 1-2 Myr) on the basin-bounding structures and attest to the episodic nature of upper-plate deformation in response to continuous subduction beneath the active margin.

Published
2013

47. From rifting to oceanic spreading in the Gulf of Aden: a synthesis

Author

P. Razin, Cynthia Ebinger, I. Al Ganad, A. Al Lazki, K. Al Toubi, Graham Stuart, Christel Tiberi, Clémence Basuyau, Elia d'Acremont, Cécile Robin, Khaled Khanbari, M. O. Beslier, Sylvie Leroy, Julia Autin, Francis Lucazeau, F. Guillocheau, J. Robinet, J. Serra Kiel, Louise Watremez, Ph. De Clarens, Abdulhakim Ahmed, Frédérique Rolandone, S. Rouzo, François Bache, P. Unternehr, Nicolas Bellahsen, Céline Baurion, Yoann Denèle, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Environnement, Géo-ingénierie et Développement (EGID), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Dalhousie University [Halifax], Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), University of Barcelona, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Géosciences Montpellier, Université des Antilles et de la Guyane (UAG)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Department of Earth and Environmental Sciences [Rochester], University of Rochester [USA], School of Earth and Environment [Leeds] (SEE), University of Leeds, Yemen Remote Sensing and GIS Center, Sana'a University, Yemen Geological Survey & Mineral Ressources Board, GSMRB, Total Exploration Production, TOTAL FINA ELF, Sultan Qaboos University (SQU), Department of Earth Sciences [Oman], Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)

Subjects
Gulf of Aden, Continental break-up, Volcanic passive margin, 010504 meteorology & atmospheric sciences, Afar plume, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, Paleontology, Segmentation, Continental margin, 0105 earth and related environmental sciences, General Environmental Science, Rift, Inheritance, Subduction, Oblique rifting, Continental margins, Transform fault, Seafloor spreading, Graben, Oceanic spreading, Tectonics, Ocean Continent transition, General Earth and Planetary Sciences, Seismology, Geology
Abstract

International audience; We present here a synthesis of the evolution of rifted continental margin systems in the Gulf of Aden. These margins are volcanic to the west of the Gulf of Aden, where they are influenced by the Afar hotspot, and non-volcanic east of longitude 46° E. The combined use of magnetics, gravity, seismic reflection, field observations (tectonic, stratigraphic and sedimentological) and oil well data allowed us to obtain better constraints on the timing of continental rifting and seafloor spreading. From the Permo-Triassic to the Oligocene, the Arabian-African plate was subject to distributed extension, probably due, at least from the Cretaceous, to tensile stresses related to the subduction of the Tethysian slab in the north. In Late Eocene-Early Oligocene, 34-33 Ma ago, rifting started to localise along the future area of continental breakup. Initially guided by the inherited basins, continental rifting then occurred synchronously over the entire gulf before becoming localised on the northern and southern borders of the inherited grabens, in the direction of the Afar hotspot. In the areas with non-volcanic margins (in the east), the faults marking the end of rifting trend parallel to the inherited grabens. Only the transfer faults cross-cut the inherited grabens, and some of these faults later developed into transform faults. The most important of these transform faults follow a Precambrian trend. Volcanic margins were formed in the west of the Gulf, up to the Guban graben in the southeast and as far as the southern boundary of the Bahlaf graben in the northeast. Seaward dipping reflectors can be observed on many oil industry seismic profiles. The influence of the hotspot during rifting was concentrated on the western part of the gulf. Therefore, it seems that the western domain was uplifted and eroded at the onset of rifting, while the eastern domain was characterised by more continuous sedimentation. The phase of distributed deformation was followed by a phase of strain localisation during the final rifting stage, just before formation of the Ocean-Continent Transition (OCT), in the most distal graben (DIM graben). About 20 Ma ago, at the time of the continental break-up, the emplacement of the OCT started in the east with exhumation of the subcontinental mantle. Farther west, the system was heated up by the strong influence of the Afar hotspot, which led to breakup with much less extension. In the Gulf of Aden (s.str), up to the Shukra El Sheik fracture zone, oceanic spreading started 17.6 Ma ago. West of this fracture zone, oceanic accretion started 10 Ma ago, and 2 Ma ago in the Gulf of Tadjoura. Post-rift deformation of the eastern margins of the Gulf of Aden can be seen in the distal and proximal domains. Indeed, the substantial post-rift uplift of these margins could be associated with either the continental break-up, or activity of the Afar hotspot and related volcanic/magmatic activity. Uplift of the northern proximal margin was still active (e.g. stepped beach rocks exposed at 60 m of 2 Ma; 30 m of 35,200 years; 10 and 2 m) and active volcanoes can be inferred at depths of between 70 and 200 km beneath the margin (at 5-10 km distance from the coast). On the distal margin, heat flow measurements show a high value that is associated with post-rift volcanic activity and the development of a volcano (with flows and sills) shortly after the formation of the OCT. The Afar hotspot is therefore important for several reasons. It allows the localisation of deformation along the Red Sea/Aden system and the rapid opening of the Gulf after the continental break-up; its influence also seems to persist during the post-rift period.

Published
2012

48. Structure and evolution of the Gulf of Lions: The Sardinia seismic experiment and the GOLD (Gulf of Lions Drilling) project

Author

Bilal U. Haq, Audrey Gailler, F. Klingelhoefer, François Bache, Junichiro Kuroda, N. Eguchi, Marina Rabineau, André W. Droxler, François Roure, Christian Gorini, Karine Alain, Maryline Moulin, Estelle Leroux, Daniel Aslanian, Philippe Schnurle, Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institute for Research on Earth Evolution [Yokosuka] (IFREE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Department of Earth Science [Houston], Rice University [Houston], Laboratoire de microbiologie des environnements extrêmophiles (LM2E), Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), IFP Energies nouvelles (IFPEN), National Science Foundation [Arlington] (NSF), GOLD project, Géosciences Marines (GM), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)

Subjects
geography, Volcanic passive margin, Rift, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Continental crust, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, Subsidence, Sedimentary basin, Pure shear, 010502 geochemistry & geophysics, 01 natural sciences, Paleontology, Geophysics, Continental margin, 13. Climate action, Lithosphere, 14. Life underwater, Seismology, 0105 earth and related environmental sciences
Abstract

International audience; The study of the deep structure and evolution of passive continental margins is important for the understanding of rifting processes and the formation of associated sedimentary basins. Since the classical models of McKenzie (1978) and Wernicke (1985), understanding how passive continental margins form, that is to say mainly the way that continental lithosphere is thinned leading to subsidence, remains one of the main challenges in the Earth sciences. Many recent observations and discoveries have modified our basic views of margin formation. The conservational models paradigm (i.e., simple shear, pure shear, or polyphase models), which exclude exchanges between lower continental crust and upper mantle and which are usually proposed to explain lithospheric stretching and consequent crustal thinning of passive continental margins, fail to completely explain all these observations. Furthermore, these models imply a large amount of horizontal movement, movements not observed in the field. In consequence, new concepts need to be built and tested.

Published
2012

49. The subsurface record of the Late Palaeozoic glaciation in the Chaco Basin, Bolivia

Author

Bache, François, Moreau, J., Rubino, J.L., Gorini, Christian, Van Vliet-Lanoë, Brigitte, GNS Science [Lower Hutt], GNS Science, Centre de Géosciences (GEOSCIENCES), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre scientifique et Technique Jean Feger (CSTJF), TOTAL FINA ELF, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), and Mines Paris - PSL (École nationale supérieure des mines de Paris)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; The Late Palaeozoic glaciation was the longest of the Phanerozoic era. It is recorded in numerous Gondwanan basins, with some, such as the Chaco Basin, having a high petroleum potential. In this basin, the quality of the available seismic, well and outcrop data permits us to characterize the Late Palaeozoic glacial record. Palaeovalleys that are c. 500 m deep and c. 7 km wide have been analysed here. Focusing on the glaciogenic Carboniferous deposits, seismic data with well ties and outcrop analogues provide new sedimentological insights. The palaeovalley infill is imaged as a chaotic seismic facies overlain by an aggrading-prograding prism, interpreted as tillites covered by a fluvio-deltaic system. Tillites form both under the ice and during rapid ice recession, whereas fluvio-deltaic systems can only originate from a stable ice margin and last until the ice sheets withdraw inland. These two depositional modes are repeated several times, generating a progressive burial of the Carboniferous palaeovalleys. This succession of erosions and fills records major glacial stages, including a series of glacial and interglacial phases from the Late Devonian to the Early Permian. Depicting the Late Palaeozoic glacial history of the Chaco Basin seems crucial for the localization of potential good reservoirs.

Published
2012

50. A two-step process for the reflooding of the Mediterranean after the Messinian Salinity Crisis

Author

Ferran Estrada, Daniel Aslanian, Rolando Armijo, Jean-Loup Rubino, Gülsen Uçarkuş, Dragana Tomić, M. Namık Çağatay, Speranta-Maria Popescu, Nikola Dumurdžanov, Ziyadin Cakir, Jean-Pierre Brun, Georges Clauzon, Ivan Zagorchev, Estelle Leroux, Jean-Pierre Suc, Laurent Jolivet, Jean-Louis Olivet, François Bache, Vesna Lesić, Bertrand Meyer, Gwenaël Jouannic, Laurent Londeix, Mihaela Carmen Melinte-Dobrinescu, Marina Rabineau, Antonio Tadeu dos Reis, Ludovic Mocochain, Dimitrios Sokoutis, Istvan Csato, Christian Gorini, Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), National Institite of Marine Geology & Geoecology, National Institute for Marine Geology and Geo-ecology (GeoEcoMar ), Instituto de Ciencias del Mar de Barcelona (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Departamento de Oceanografia Geologica, Universidade do Estado do Rio de Janeiro [Rio de Janeiro] (UERJ), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Ss. Cyril and Methodius University in Skopje (UKIM), Geological Institute of BAS, Bulgarian Academy of Sciences (BAS), Geolomagnetic Institute, ITU (GEOLOGY AND MINING DEPARTMENT), Istanbul Technical University (ITÜ), ISES, Vrije Universiteit Amsterdam [Amsterdam] (VU), Department of Geology, Collin Collège, Maden Fakültesi = Faculty of mines [Istanbul], Sytèmes Tectoniques, Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), CNRS-INSU AMEDITER CNRS-INSU TerMex, ANR-06-BLAN-0156,EGEO,Rhéologie et déformation de la lithosphère égéenne(2006), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Unité de recherche Géosciences Marines (Ifremer) (GM), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Sts Cyril and Methodius University, Faculty of mining and geology, University of Belgrade [Belgrade]-University of Belgrade [Belgrade], Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre National de la Recherche Scientifique (CNRS)-Institut d'écologie et environnement-Observatoire des Sciences de l'Univers-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), National Institute of Marine Geology and Geo-ecology (GeoEcoMar ), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de géologie de l'ENS (LGE), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Geological Institute, Istanbul Technical University, Systèmes Tectoniques, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), School of Mines and eurasia Institute of Earth Sciences, and Tectonics

Subjects
decic basin, 010504 meteorology & atmospheric sciences, Evaporite, Aardwetenschappen, [SDE.MCG]Environmental Sciences/Global Changes, northern apennines, Diachronous, Structural basin, sea level, 010502 geochemistry & geophysics, di tetto formations, 01 natural sciences, Mediterranean Basin, Paleontology, miocene pliocene boundary, Stratotype, Mediterranean sea, paleo environmental changes, earliest zanclean age, 14. Life underwater, SDG 14 - Life Below Water, reflooding, Sea level, 0105 earth and related environmental sciences, [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics, desiccated deep basin, southern France, Geology, 6. Clean water, subsidence studies, Oceanography, 13. Climate action, Subaerial, section marche province, depositional environments
Abstract

Bache, François ... et. al.-- 29 pages, 22 figures, 1 table, additional supporting information may be found in the online version of this article: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2117.2011.00521.x/suppinfo, The Messinian Salinity Crisis is well known to have resulted from a significant drop of the Mediterranean sea level. Considering both onshore and offshore observations, the subsequent reflooding is generally thought to have been very sudden. We present here offshore seismic evidence from the Gulf of Lions and re-visited onshore data from Italy and Turkey that lead to a new concept of a two-step reflooding of the Mediterranean Basin after the Messinian Salinity Crisis. The refilling was first moderate and relatively slow accompanied by transgressive ravinement, and later on very rapid, preserving the subaerial Messinian Erosional Surface. The amplitude of these two successive rises of sea level has been estimated at ≤500 m for the first rise and 600-900 m for the second rise. Evaporites from the central Mediterranean basins appear to have been deposited principally at the beginning of the first step of reflooding. After the second step, which preceeded the Zanclean Global Stratotype Section and Point, successive connections with the Paratethyan Dacic Basin, then the Adriatic foredeep, and finally the Euxinian Basin occurred, as a consequence of the continued global rise in sea level. A complex morphology with sills and sub-basins led to diachronous events such as the so-called 'Lago Mare'.This study helps to distinguish events that were synchronous over the entire Mediterranean realm, such as the two-step reflooding, from those that were more local and diachronous. In addition, the shoreline that marks the transition between these two steps of reflooding in the Provence Basin provides a remarkable palaeogeographical marker for subsidence studies. © 2011 Blackwell Publishing Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists, This work is a contribution to ANR ‘EGEO’ Project, to CNRS/INSU ‘Actions Marges’ Project (AMEDITER), and to ‘Bassins ne´oge`nes et manteau en Méditerranée’ (TerMEx CNRS/INSU)

Published
2012

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