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11. Cross-shelf trough and ice-stream lineations in the 440 Ma Late Ordovician rocks of northern Africa mapped from high-resolution satellite imagery

Author

Moreau, J., Ghienne, J.-F., Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Institut de physique du globe de Strasbourg (IPGS), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

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

International audience

Published
2016
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12. Erratum: Corrigendum to 'Diatom, phytolith, and pollen records from a 10Be/9Be dated lacustrine succession in the Chad basin: Insight on the Miocene–Pliocene paleoenvironmental changes in Central Africa' (Palaeogeography, Palaeoclimatology, Palaeoecology (2015) 430 (85–103) (S003101821500214X) (10.1016/j.palaeo.2015.04.013))

Author

Novello, A., Lebatard, A.-E., Moussa, A., Barboni, Doris, Sylvestre, F., Bourles, D.L., Paillès, Christine, Buchet, G., Decarreau, A., Duringer, P., Ghienne, J.-F., Maley, J., Mazur, Jean-Charles, Roquin, C., Schuster, M., Vignaud, P., Institut International de Paléoprimatologie, Paléontologie Humaine : Evolution et Paléoenvironnement (IPHEP), Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), 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), LTI, ENSA de Tanger, Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers-Centre National de la Recherche Scientifique (CNRS), Centre de géochimie de la surface (CGS), Centre National de la Recherche Scientifique (CNRS)-Université Louis Pasteur - Strasbourg I-Institut national des sciences de l'Univers (INSU - CNRS), 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), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-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), Laboratoire des technologies Innovantes [Tanger] (LTI), Ecole Nationale des Sciences Appliquées [Tanger] (ENSAT), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut de Chimie du CNRS (INC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), 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), Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE)

Subjects
[SDU]Sciences of the Universe [physics], [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries), ComputingMilieux_MISCELLANEOUS
Abstract

cited By 0; International audience; no abstract

Published
2016
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13. Deciphering channel networks from aeromagnetic potential field data: the case of the North Sea Quaternary tunnel valleys.

Author

Brahimi, S, Le Maire, P, Ghienne, J F, and Munschy, M

Subjects
MAGNETIC anomalies, VALLEYS, TUNNELS, MAGNETIC susceptibility, GEOMETRIC approach
Abstract

High-resolution magnetic data and potential field methods have been used to perform a detailed analysis of networks of late Quaternary subglacially cut tunnel valleys (central Viking Graben, Norwegian sector of the North Sea). High-frequency, ribbon-like, sinuous, paired magnetic anomalies interpreted to be the signature of tunnel valleys are identified. Such magnetic anomalies have 1–8 nT amplitudes and reflect a magnetic susceptibility contrast between valley infills and the host sediments. Fractional vertical derivative and horizontal gradient transforms provide the best control on the accurately delineation of tunnel valleys by plotting automatically the extrema. The 2-D forward modelling is a very effective approach to determine the geometric parameters and magnetic susceptibility of the modelled valleys. It allows us to determine the finite-width flat horizontal thin geometry as the most appropriate simple geometry to simulate the magnetic anomaly linked to a channel structure. The application of Euler deconvolution using complex algebra allows us to substantiate the structural index (n  = 1.5) for simple palaeovalley geometries and to determine fair valley depth estimates. [ABSTRACT FROM AUTHOR]

Published
2020
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15. Phytolith records from a 10Be/9Be dated lacustrine succession in the Lake Chad basin: insight on the Pliocene palaeoenvironmental changes in Central Africa

Author

Novello, A., primary, Lebatard, A.-E., additional, Moussa, A., additional, Barboni, D., additional, Sylvestre, F., additional, Bourlès, D.L., additional, Paillès, C., additional, Buchet, G., additional, Decarreau, A., additional, Duringer, P., additional, Ghienne, J.-F., additional, Mazur, J.-C., additional, Roquin, C., additional, Schuster, M., additional, and Vignaud, P., additional

Published
2016
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18. Ordovician chitinozoans and acritarchs from southern and southeastern Turkey Chitinozoaires et acritarches ordoviciens du sud et du sud-est de la Turquie

Author

Paris, Florentin, Le Hérissé, Alain, Monod, Olivier, Kozlu, Huseyin, Ghienne, J.-F., T. Dean, W., Vecoli, Marco, Günay, Y., 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)-Centre Armoricain de Recherches en Environnement-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), Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), TPAO, Exploration Group, Ecole et Observatoire des sciences de la terre (EOST), Centre National de la Recherche Scientifique (CNRS)-Université Louis Pasteur - Strasbourg I-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de paléontologie et paleogéographie du paleozoique (LPPP), Université de Lille, Sciences et Technologies-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ECLIPSE - Programme INSU, Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Acritarchs, Turkey (S and SE), Stratigraphy, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Ordovician, Chitinozoans, Palaeogeography
Abstract

International audience; Revision of the lithostratigraphy of Ordovician deposits in southern and southeastern Turkey led to a re-evaluation of the age assignments of formations identified in the subsurface and at outcrop. Previous datings were based on macrofauna (mainly trilobites and graptolites). The present paper focuses exclusively on organic-walled microfossils (chitinozoans and acritarchs), which provide numerous chronostratigraphical improvements, especially in successions barren or poor in macrofossils. Close to 200 samples were collected in the Taurus chain (i.e. from Kemer, Seydisehir, Ovacik, Kozan, to Sariz regions in southern Turkey) and in the Border Folds (Mardin and Hakkari regions), usually regarded as part of the Arabian Plate in palaeogeographical reconstructions. Many samples are productive and yield chitinozoans and/or acritarchs of extremely variable preservation, depending on their geographical and geological location. In the Taurus chain, the material is “coalified” and frequently fragmented whereas, in the Border Folds, maturation of the organic matter is much lower and preservation of the microfossils is good to excellent. Several Ordovician chitinozoan biozones (northern Gondwana zonation) as well as diagnostic acritarch assemblages are identified in southern and southeastern Turkey. These Ordovician formations are assigned here to the new global stages of the Ordovician chronostratigraphical scale. The Seydisehir (upper part), Sobova, and Kilgen Lake (lower part) formations are referred to the Darriwilian. The Kilgen Lake (upper part), Sort Tepe, and Bedinan formations are attributed to the Sandbian and to the Katian, and the Halevikdere Formation (glacio-marine part) is assigned to the Hirnantian. Reworking of Early Ordovician acritarchs is documented in pre-glacial and in glacial Late Ordovician deposits. They indicate that active erosive processes occurred during the Middle and Late Ordovician sedimentation. The organic-walled microfossils recorded in the Ordovician of south and southeastern Turkey belong to the northern Gondwana realm. Interestingly however, some Baltoscandian influences are noted in the Border Folds during Early Late Ordovician.

Published
2007
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19. Wind-driven waterbodies: a new category of lake within an alternative sedimentologically-based lake classification.

Author

Nutz, A., Schuster, M., Ghienne, J.-F., Roquin, C., and Bouchette, F.

Subjects
HYDRODYNAMICS, GEOMORPHOLOGY, SEDIMENTOLOGY, PALEOLIMNOLOGY, BEACH ridges
Abstract

Lakes are common natural systems for which sedimentation is considered to be relatively simple, generally dominated by fluvial processes along the margin and prevailing low-energy settling in the central, deeper parts. However, for many lakes, higher-energy wind-driven processes dominate. As such, a new category of lakes is proposed, herein referred to as wind-driven waterbodies (WWB). WWB display a sedimentation largely dominated by wave related processes and wind-induced lake-scale water circulation evidenced by the construction of beach ridges, spits or cuspate spits along their shorelines, and by sediment drifts, sedimentary shelf progradation and erosional surfaces in their deeper, offshore domains. WWB are observed worldwide, they share a common physiography that favours wind-forced hydrodynamics and related sedimentation patterns. This physiography is expressed by the I index, a ratio of the maximum representative fetch relative to mean basin depth. It is proposed that an index value greater than three favours the evolution of a lake as a WWB. The WWB concept represents a new end-member in an alternative, sedimentologically-based lake classification that is proposed in this paper. [ABSTRACT FROM AUTHOR]

Published
2018
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20. Nature et dynamique des systèmes sédimentaires continentaux d'Afrique au Mio-Plio-Quaternaire : exemple des séries à Hominidés anciens des Bassins du Turkana et du Tchad

Author

Mathieu Schuster, Jean-Jacques Tiercelin, Ph. Duringer, Ghienne, J. F., Vignaud, P., Hélène Roche, Brunet, M., Macgregor, Benedicte, Préhistoire et Technologie (PréTech), and Université Paris Nanterre (UPN)-Centre National de la Recherche Scientifique (CNRS)

Subjects
bassin du Turkana, plio-pleistocène, [SHS.ARCHEO] Humanities and Social Sciences/Archaeology and Prehistory, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, Systèmes sédimentaires, miocène, Bassin du Tchad, Afrique orientale
Abstract

(ASF, Giens, 11-13 octobre 2005)

Published
2005

21. Datation par les chitinozoaires des principaux épisodes transgressifs identifiés dans l'Ordovicien du Sahara Algérien

Author

Boumendjel, K., AÏt Salem, H., Paris, F., Ghienne, J.-F., Videt, B., Zelouf, K., Centre de géochimie de la surface (CGS), Centre National de la Recherche Scientifique (CNRS)-Université Louis Pasteur - Strasbourg I-Institut national des sciences de l'Univers (INSU - CNRS), Aunis, Danièle, and Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SDU.STU.ST] Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SDU.STU.PG] Sciences of the Universe [physics]/Earth Sciences/Paleontology, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
Published
2004

22. Late Wisconsinan grounding zones of the Laurentide Ice Sheet margin off the Québec North Shore (NW Gulf of St Lawrence)

Author

Lajeunesse, P., Dietrich, P., and Ghienne, J.-F.

Abstract

Swath bathymetry data and seismic profiles collected in the NW Gulf of St Lawrence reveal a series of wedge-shaped depositional systems interpreted as grounding zone wedges (GZWs). Some segments of the GZWs change locally to form frontal moraines, or morainal banks, and subaqueous ice-contact fans, reflecting changes in either the nature of the ice margin or the rate of sediment input. These grounding zones (GZ) of the ice margin extend laterally along three isobaths at depths of 180 (GZ1), 120 (GZ2) and 80 (GZ3) m (±20 m) along the Québec North Shore shelf, the 120 m-deep GZ2 system being traceable over a distance of >300 km. Associated GZWs can occur in three geometries along a same isobath system: curvilinear, lobate and shelf-break. GZ systems were built during three distinct stages of stabilization of the marine-based southeastern margin of the Laurentide Ice Sheet following its rapid retreat across the deeper waters of the Laurentian Channel in the Gulf of St Lawrence after 14.8 cal ka BP. The occurrence of GZ along distinct isobaths indicates that bathymetry exerted a strong control on ice stabilization during deglaciation by reducing the relative water depth at the ice margin and thereby the buoyancy and rate of iceberg calving. However, fluctuations and re-advances of the ice margin are also recorded by the overprinting of a portion of the GZ2 system by the younger GZ3 system, potentially suggesting an additional response to climate-driven forcing.

Published
2019
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23. Late Ordovician glaciation in southern Turkey

Author

Monod, Olivier, Kozlu, H., Ghienne, J.-F., T. Dean, W., Günay, Y., Le Hérissé, Alain, Paris, Florentin, Robardet, M., Institut des Sciences de la Terre d'Orléans (ISTO), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), TPAO, TPAO, Exploration Group, Ecole et Observatoire des sciences de la terre (EOST), Centre National de la Recherche Scientifique (CNRS)-Université Louis Pasteur - Strasbourg I-Institut national des sciences de l'Univers (INSU - CNRS), Department of Geology, National Museum, 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 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)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre Armoricain de Recherches en Environnement-Centre National de la Recherche Scientifique (CNRS)

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

We present a new survey of several Palaeozoic sections in both the Taurus range and the Border Folds that documents typical glacial features including a glacial pavement and striated dropstones (Halevikdere Formation) and demonstrates the former presence of an ice sheet in southern and south-eastern Turkey. Evidence for the late Ashgill (Hirnantian) age of this episode is provided by macro- and microfossils found within the glacial formation. The extension of ice-related deposits into the northernmost part of the Arabian Platform (Mardin region) implies a much wider distribution of the Ordovician ice sheet than was previously believed, and strongly suggests that southern Turkey lay close to Egypt during the Lower Palaeozoic.

Published
2003
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