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International audience; Phylogenetic studies of present-day terrestrial organisms suggest that faunal dispersals between South America and the Greater Antilles may have occurred during the Cenozoic through the Lesser Antilles. However, because of the lack of geological data to unravel the areas that may have emerged along the Lesser Antilles trench, the migration paths used by their ancestors remain unknown. Here, we present novel paleogeographic maps of the central Lesser Antilles (extending from Guadeloupe to Martinique islands) which are built on the basis of onshore and offshore stratigraphic correlations (50 seismic lines, biostratigraphy of 9 dredged and 29 field samples, six sedimentary logs). We find that repetitive episodes of uplift and drowning have occurred in the central part of the Lesser Antilles during the Neogene. Offshore, the Marie-Galante Basin comprises three sedimentary megasequences that deposited between: (i) the Oligocene and Early Miocene, including the extinct arc, (ii) the Middle and Late Miocene and (iii) the latest Miocene and Holocene. These sediments infill a NNW-SEE trending forearc rift that opened during the Early Miocene. The megasequences are separated by subaerial regional unconformities that affect the rift shoulders. Onshore, we show that the lower part of the carbonate platform in Guadeloupe and La Désirade has deposited during the late Messinian. In Martinique, we refine the age of the carbonate deposits belonging to the extinct arc to the Chattian-Burdigalian, and evidence a major subaerial unconformity corresponding to the Middle Miocene. We propose that between Anguilla and Martinique, from north to south, large archipelagos, which are now drowned, have existed during the early Middle Miocene and the latest Miocene. We suggest that during the Miocene, the Lesser Antilles may have been used as a pathway for land-faunal dispersals from South America.

International audience; Unlike most Neogene basins of the Betic Cordillera where the Salinity Crisis is dated to the Messinian, a contradictory Tortonian dating was proposed for evaporites of the Lorca Basin. As a consequence, complex structural models have been proposed in the literature to explain this discrepancy in the timing of evaporites. In order to integrate the Lorca Basin into the geological context of the western Mediterranean domain during the Late Miocene, new sedimentological and stratigraphical studies coupled with new dating were performed, which allow us to propose a Messinian age for both diatomite-bearing deposits and evaporites of the Lorca Basin. These new ages challenge the idea of a Tortonian salinity crisis in the Lorca Basin. Three main events of base-level drop were evidenced during the Messinian. Each event is correlated with successive steps of basin restriction. Shallow salina evaporites were deposited after a base-level fall during the Messinian before a final base-level drop, which led to the entire exposure of the basin. This last exposure is interpreted as coeval with the deposition of first evaporites and halite in the deep Mediterranean basins. The reflooding which allowed the deposition of brackish deposits and a short-lived marine incursion occurred at the end of the Messinian. Base-level drops occurred during eustatic falls amplified by the gradual uplift of the Betic Cordillera. The exhumation of the Tercia ridge along the strike-slip Alhama de Murcia fault system during the Messinian probably favoured the gradual restriction of the basin. A discussion on correlations of main unconformities between several Neogene basins of the Betics is proposed, suggesting a similar structural evolution at the regional scale.

Our study aims to reconstruct the palaeogeography of the northern part of the Lesser Antilles in order to analyse whether emerged areas might have existed during the Cenozoic, favouring terrestrial faunal dispersals between South America and the Greater Antilles along the present-day Lesser Antilles arc. The stratigraphy and depositional environments of the islands of Anguilla, St Martin, Tintamarre, St Barthélemy, Barbuda and Antigua are reviewed in association with multichannel reflection seismic data acquired offshore since the 80's in the Saba, Anguilla and Antigua Banks and in the Kalinago Basin, including the most recent academic and industrial surveys. Seven seismic megasequences and seven regional unconformities are defined, and calibrated from deep wells on the Saba Bank and various dredges performed during marine cruises since the 70's in the vicinity of the islands. Onshore and offshore correlations allow us to depict an updated and detailed sedimentary organisation of the northern part of the Lesser Antilles from the late Eocene to the late Pleistocene. Paleogeographic reconstructions reveal sequences of uplift and emergence across hundredswide areas during the late Eocene, the late Oligocene, the early middle-Miocene and the latest Miocene-earliest Pliocene, interspersed by drowning episodes. The ∼200 km-long and ∼20 km-wide Kalinago Basin opened as an intra-arc basin during the late Eocene - early Oligocene. These periods of emergence may have favoured the existence of episodic mega-islands and transient terrestrial connections between the Greater Antilles, the Lesser Antilles and the northern part of the Aves Ridge (Saba Bank). During the Pleistocene, archipelagos and mega-islands formed repeatedly during glacial maximum episodes.

This paper presents the correlation between the geomorphological features of the Sl��nicul de Buz��u Valley and the geological ones, such as the tectonic regime and the type of rocks. We are pointing out that the geomorphology of the valley and the change of the flow direction are linked to the type of rocks and tectonic elements of traversed geological structures. The change of the upper course of the river from NS to WE upstream the Lop��tari locality coincides with a major tectonic element, a digitation occurring in the deposits formed by hard compact Paleogene rocks. The upper course deep valley is replaced by a larger one in the sector that exposed Miocene and Pliocene deposits, showing a W-E direction. The lower course of the river shows again a change in the course direction from N towards S, up to its confluence with the Buz��u River. This modification corresponds to the occurrence of the friable Pliocene, Pleistocene and Holocene deposits, such as sandstones, clays, marls and weakly consolidated ones, i.e., sands and loess., {"references":["Chendeș V. (2011). Resursele de apă din Subcarpații de la Curbură. Evaluări geospațiale. Ed. Academiei Române, 339 p.","Dumitrescu I., Săndulescu M., Bandrabur T., Săndulescu M. (1968). Covasna Sheet, scale 1:200,000. Printed by the Geological Institute of Romania.","Grecu F., Comănescu L. (2006). The morphometric analysis of the gravels from the Slănic of Buzău bed – preliminary considerations. Revista de geomorfologie, 8: 45-52.","Jipa D., Olariu C. (2009). Dacian Basin: Depositional Architecture and Sedimentary History of a Paratethys Sea. Geo-Eco-Marina Special Publication, 3, 264 p.","Melinte M. (2005). Oligocene palaeoenvironmental changes in the Romanian Carpathians, revealed by calcareous nannofossil fluctuation. 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Seven Middle Miocene (Upper Badenian to Lower Sarmatian) sedimentary sections of the Central Paratethys, two from the Polish Carpathian Foredeep Basin (PCFB) and five from the Eastern Carpathian Foreland Basin (ECFB) of Romania and the Republic of Moldova have been analysed micropalaeontologically to better constrain the Badenian-Sarmatian Extinction Event, characterized by significant taxonomic impoverishment of both foraminifers and ostracods. Our studies show significant palaeoenvironmental changes in the basin including depth, salinity, oxygenation, and organic matter flux. The occurrence of moderately diverse planktonic foraminifera (Globigerina, Globigerinita, Globorotalia, Trilobatus, Orbulina, Velapertina) in the Upper Badenian deposits of the PCFB as well as in the ECFB and their rarity in the lowermost Sarmatian indicate an almost fully marine environment during the latest Badenian, followed by a significant regression and possible appearance of much more restricted marine conditions across the boundary. The taxonomic composition of the Sarmatian foraminifera, ostracoda and calcareous nannofossils indicate that during this interval the salinity fluctuated strongly, with the water regime varying from brackish to normal marine. In addition, the identified micropalaeontological assemblages identified show palaeoenvironmental similarity across different basins of the Central Paratethys. This supports a hypothesis of possible connections during the latest Badenian between different areas of the Central Paratethys, as well as of the existence of a gateway between the Central Paratethys and the Mediterranean realm

Reconstructing orogenic systems made up dominantly by sediments accreted in trenches is challenging because of the incomplete lithological record of the subducted oceanic domain and its attached passive continental margin thrusted by collisional processes. In this respect, the remarkable ~600 km long continuity of sediments exposed in the Eastern Carpathian thin-skinned thrust and fold belt and the availability of quantitative reconstructions for adjacent continental units provide excellent conditions for a paleogeographical study by provenance and sedimentological techniques constraining sediment routing and depositional systems. These sediments were deposited in the Ceahl?u-Severin branch of the Alpine Tethys Ocean and over its European passive continental margin. We report sedimentological, paleomagnetic, petrographic, and detrital zircon U-Pb data of Lower Cretaceous sediments from several thin-skinned tectonic units presumably deposited in the Moldavides domain of the Eastern Carpathians. Sedimentological observations in the innermost studied unit demonstrate that deposition took place in a deepwater basin floor sheets to sandy turbidite system. Detrital zircon age data demonstrate sourcing from internal Carpathian basement units. The sediment routing changes in more external units, where black shales basin floor sheets to sandy mud turbidites were sourced from an external, European continental area. Although some degree of mixing between sources located on both margins of the ocean occurred, constraining a relatively narrow width of the deep oceanic basin, these results demonstrate that the internal-most studied unit was deposited near an Early Cretaceous accretionary wedge, located on the opposite internal side relative to the passive continental margin domain of other Moldavides units.

International audience; The phosphate series of the Moroccan High Atlas accumulated during the Upper Cretaceous-Paleogene phosphogenic period, on a biologically-productive shallow-water platform. These phosphate-rich sediments were deposited during a relative sea-level cycle generating major stratigraphic surfaces. Five different types of phosphatic lithofacies are recognized based on their petrographic and sedimentologic features. The pristine phosphate lithofacies corresponds to phosphatic marls formed by francolite authigenesis within the outer platform domain below the storm wave-base (primary phosphogenesis zone). This primary phosphatic lithofacies can be differentiated as a result of the interaction between hydrodynamic autocyclic processes and allocyclic forcing. Accordingly, the granular phosphate lithofacies was formed by in-situ storm and bottom currents that winnowed the pristine phosphate. This winnowed lithofacies, composed of densely-packed peloids, shows relatively high P2O5 concentrations. The turbiditic phosphate resulted from the basinward transport and deposition of other phosphate types by gravity flows leading to normally-graded phosphatic sediment. The phosphatic lags were formed by wave reworking and transporting of pristine and associated granular facies within the inner platform. The karst-filling phosphate corresponds to former phosphate types transported by early transgressive currents and trapped within karstic pockets as phospharudites. The distribution of the different phosphate types across the margin and within the depositional sequences is controlled by the effects of relative sea-level changes. The pristine phosphate and associated winnowed facies are found above the major maximum flooding surface, which is dated by nannoflora to the Selandian-Thanetian transition. The phosphatic turbidites occurred during periods of high sea-level. The karst-related phosphatic facies accumulated during early transgressive stages. The phosphatic lags accumulated mainly during the regressive phases of third and fourth-order sequences. The accumulation processes of the different phosphatic lithofacies control the ore grade of the phosphatic sediments: repeated storm-induced winnowing of pristine phosphate contributes to the enrichment of the phosphate ore grade.

The Danube River with a length of 2,800 km is the second longest European river after the Volga. As the Danube River crosses multiple sedimentary basins (Vienna, Pannonian, Dacian) its drainage basin covers a variety of geological units of the Alps, Carpathians, Dinarides and Balkans; hence, its tributaries contain a large sedimentary diversity. Detrital zircon (DZ) studies are appropriate for understanding the pattern of orogenic erosion, sediment routing and mixing of different signals during the transport and preservation of the river sediments. This work presents U-Pb geochronology data obtained from modern sediments of seven tributaries in the Lower Danube: Cerna, Topolniţa, Jiu, Olt, Argeş, Ialomiţa and Siret. Additionally, 1 sample was collected from the Danube Delta front.The studied samples exhibit several main peaks, which are from oldest to newest: (i) Cambro-Ordovician, linked to the backarc basins and island arcs of Peri-Gondwana subduction (600 – 440 Ma); (ii) Lower to Middle Carboniferous from Variscan magmatic and metamorphic rocks (350 – 320 Ma), showing significant values in most analysed samples; iii) Alpine, younger than 100 Ma, most probably related to the Southern Carpathian Late Cretaceous Banatitic arc and to the Neogene volcanism of the Eastern Carpathians and Apuseni Mountains. The obtained ages on the DZ geochronology show downstream mixing, similarly to recent published data focused on the sediment provenance studies (Balintoni et al., 2014; Ducea et al., 2018).For the Lower Danube western investigated samples, our results show as main source the metamorphic rocks characteristic for the Upper and Lower Danubian tectonic units of the Southern Carpathians (ca. 300 Ma). Some larger tributaries in the eastern (downstream) Lower Danube show temporal disperse peaks on the DZ geochronology, feature probably reflecting successive processes of recycling. Notably, the most representative sources of DZ identified in the samples from easternmost Lower Danube tributaries are the Varistic metamorphites.The results suggests that the sediments of the western studied tributaries, characterized by small drainage basin, are mainly composed by igneous and metamorphic rocks. The eastern tributaries with larger drainage basins and therefore a much-varied type of rocks show a more complex DZ distribution; probably, only a small amount of DZ grains indicates the “primary” source rock. The sample from the Danube Delta Front yielded a wide DZ distribution, mirroring the huge amount of sedimentary material from various sources belonging to all basins crossed by the Danube.The financial support for this paper was provided by the Romanian Ministry of Research and Innovation, through the Programme Development of the National System of Research – Institutional Performance, Project of Excellence for Rivers-Deltas-Sea systems No. 8PFE/2018.References:Balintoni, I., Balica, C., Ducea, M.N., Hann, H.P. (2014). Peri-Gondwanan terranes in the Romanian Carpathians: A review of their spatial distribution, origin, provenance and evolution. Geoscience Frontiers 5: 395–411.Ducea, M.N., Giosan, L., Carter, A., Balica, C., Stoica, A.M., Roban, R.D., Balintoni, I., Filip, D., Petrescu, L. (2018). U-Pb detrital zircon geochronology of the Lower Danube and its tributaries; implications for the geology of the Carpathians. Geochemistry, Geophysics, Geosystems, 19(9), 3208-3223.

The Danube Deep-Sea Fan, situated in NW Black Sea, is one of the most developed deep-sea sedimentary structures in Europe (Panin & Jipa, 2002). In 2018, in the framework of the uBiogas Project (24PCCDI/2018), several cores were acquired from the aforementioned area. In this study, high resolution microfaunal analyses coupled with sedimentological and geochemical ones, were performed on two gravity cores that revealed changes since the Last Glacial Maximum. The cores have been collected from two secondary canyons, situated in the E of the Danube Canyon, at 655,7 m (MN183_3_GC_1) and 1315 m water depths (MN183_8_GC_1). In both cores, three stratigraphic units as described by Ross & Degens (1974) were identified (oldest first): Unit 3 (Lacustrine lutite), Unit 2 (Sapropel Mud) and Unit 1 (Coccolith Mud).The sediments of Unit 3 correspond to the Last Glacial Maximum and are marked by the presence of the cold-water ostracod species. The cores contain a reddish-brown clay and silty interval belonging to the post-glacial melt-water pulse of the Heinrich Event 1. In these deposits the ostracod assemblages display a high diversity and abundance. The CaCO3 amount is very low, i.e. below 15%, except for the upper part where it reaches more than 50%. The samples of Unit 3 contain nannofossil assemblages that are entirely composed of reworked species from Cretaceous, Paleogene, Early and Middle Miocene intervals.In Unit 2 (the sapropel), very few specimens of ostracods were identified, towards the top. During this depositional interval CaCO3 values are dropping again below 15%. The high abundance of the calcareous nannoplankton species Braarudosphaera bigelowii in the upper part of Unit 2 suggests the first strong influx of marine waters into the Black Sea basin.In the youngest Unit 1, a brackish-marine ostracod assemblage, with low diversity and abundance was identified. This interval is characterized by the presence of polyhaline ostracods with Mediterranean origin. The ostracods from this assemblage tolerate salinities comprised between 17-21 ‰ and characterize a sub-littoral environment. The CaCO3 values are increasing to more than 50%. During the depositional interval of Unit 1 the environmental was definitely a marine one, probably with a constant salinity of surface waters over 17 ppm, allowing the calcareous nannoplankton species Emiliania huxleyi and Braarudosphaera bigelowii to proliferate. The great abundance of the two taxa and especially of Emiliania huxleyi indicates the existence in the basin of a high nutrient input.The financial support for this paper was provided by the Romanian Ministry of Research and Innovation, through the Programme 1 – Development of the National System of Research – Institutional Performance, Project of Excellence in Research-Innovation, Contract No. 8PFE/2018 and by the Project uBiogas, contract no. 24PCCDI/ 2018. Panin, N., Jipa, D., 2002. Danube river sediment input and its interaction with the northwestern Black Sea. Estuarine Coastline Shelf Science 54: 551–562.Ross, D.A., Degens, E.T., 1974. Recent sediments of the Black Sea. In: Degens E.T. and Ross D.A. (Eds.), The Black Sea: Geology, Chemistry, and Biology. American Association of Petroleum Geologists, Tulsa, USA: 183–199.

We provide new data on the Black Sea evolution during the preconnection and reconnection stages with the Mediterranean, based on sedimentology, geochemistry, calcareous nannoplankton and ostracods analysis, in 13 cores placed between 141 m and 1315 m water depths. Unit 1 – The Coccolith Mud, Unit 2 - The Sapropel Mud and Unit 3 – The Lacustrine Lutite, including red-brownish depositional intervals, were identified in all studied deep-water cores. These units are not present in a shallow setting, i.e., above 166.7 m water depth, being replaced by sandy levels and shell debris. The red-brownish layers are interpreted as hyperpycnites, but some of the red successions show turbidite features, especially the ones situated on canyon sides, at a water depth below 600 m. In the oldest intercepted Unit 3 of the Neoeuxinian lake, CaCO3 values are constantly low, but towards the top of this unit they show two distinct peaks, interpreted as signals of Bolling–Allerod and Preboreal interstadials. In between, a significant decrease in CaCO3 values, linked to the setting of the Younger Dryas, is coincident in the deep cores with diatom blooms and high frequency of ostracods related to cooler waters. The scarce but continuous occurrence of Emiliania huxleyi nannoplankton species from the top of Unit 3 indicates that the salinity was at least 10–11‰ prior the Sapropel Mud deposition and increase at a least 17‰ within the lower part of Unit. 2. In the same interval, the Ponto-Caspian ostracods are still present. The Mediterranean ostracods consistently occur from the top of Unit 2, when bottom water salinity reached values for allowing their survival. The first bloom of E. huxleyi is placed at the base of Unit 2, where coccolith laminae occur, while the second bloom is placed in Unit 1 that contains exclusively Mediterranean ostracods and consistent assemblages of benthonic foraminifers, similar with the ones present today.

Widespread evaporites were deposited in large parts of the Central Paratethys during the so-called Badenian Salinity Crisis (BSC). The adverse environmental conditions that accompanied the BSC triggered a demise in the basin's marine fauna, inducing the so-called middle-Badenian-extinction-event. While tectonic activity preconditioned the Central Paratethys for isolation, it has recently been shown that the BSC was eventually triggered by the base-level drop accompanying the Mi3b global cooling event, which terminated the Middle Miocene Climatic Optimum. Here, we provide new constraints on the termination of the BSC by 40Ar/39Ar dating of a volcanic ash layer, located in a marl succession several meters above the Badenian evaporites of the Slănic Syncline in the Romanian East Carpathians. The results reveal that the BSC ended before 13.32 ± 0.07 Ma. Comparison with previously obtained geochronological results in Poland constrains the duration of the BSC to 500 kyr, assuming evaporite deposition in the Central Paratethys occurred as one event. The obtained 40Ar/39Ar results are complemented with paleomagnetic and micropaleontological analyses. These reveal that the investigated post-BSC marl interval in the Slănic Syncline was deposited in a period of reversed polarity corresponding to C5AAr. This is in agreement with calcareous nannoplankton from the same interval that belong to the NN6 zone. Ostracod and foraminifera marker species are indicative of the middle part of the regional Badenian stage, traditionally known as the Wielician. The foraminiferal assemblage is nevertheless very similar to Serravallian assemblages from the Mediterranean, which suggests that, in addition to a connection between the Central Paratethys and the Eastern Paratethys, there was a marine connection with the Mediterranean following the BSC. A comparison with post-BSC successions in Ukraine and Poland illustrates that the BSC was terminated by a transgression that re-installed normal marine conditions in the Carpathian foredeep. This basin-wide transgression resulted from reconnection of the Carpathian Foreland Basin with the Mediterranean and Eastern Paratethys, which improved the exchange of water and fauna. Global eustacy cannot explain re-connection of these basins, because global sea level on average remained just as low after the BSC as it had been during the crisis. The improved interconnectivity between the basins must therefore have been primarily caused by tectonic modification of the interconnecting gateways. Geodynamics thus played a crucial role in the re-establishment of a flourishing marine environment.

The Paleocene–Eocene Thermal Maximum (PETM) event was a dramatic global warming ∼55.93 Ma ago that resulted in biological extinction events, lithological changes, and major deviations in δ13C and δ18O. The southwestern Tarim Basin of China exposes successive Paleogene strata as a result of Tethys evolution and is considered an ideal region for PETM research.Based on calcareous nannoplankton biostratigraphy, we also used stable isotopes and XRD to analyse the Paleocene–Eocene transition in the Tarim Basin. At the Bashibulake Section, the PETM interval is characterized by (1) an abrupt negative shifts in δ13Corg, δ13Ccarb and δ18O (−3‰, −4.5‰ and −3‰ respectively); (2) an obvious negative correlation between the K-mode (Discoaster, Fasciculithus, Ericsonia, Sphenolithus and Rhomboaster) and r-mode (Biscutum, Chiasmolithus, Toweius) nannofossil taxa coincident with a robust Rhomboaster-Discoaster assemblage; and (3) a significant increase in the percentage of detrital input along with an increase in gypsum content. In the upper part of the Qimugen Formation Micrantholithus and Braarudosphaera are commonly found right up to the top where most of the nannofloras suffer a sharp decrease. In the overlying Gaijitage Formation, calcareous nannofossils disappear completely. These events indicate that the southwestern Tarim Basin was a warm shallow continental shelf during the deposition of the Qimugen Formation. From the early Eocene, the environment changed conspicuously. Evaporation increased and sea level fell, which led to an acid climate. This climate mode continued within the youngest unit studied, the Gaijitage Formation, characterized by the deposition of thick evaporates. Consequently, most of the marine plankton, i.e. calcareous nannoplankton, became disappear, because of the significant climate shift. Keywords: Calcareous nannofossil, Biostratigraphy, Paleocene–Eocene Thermal Maximum (PETM), Tarim Basin

During the Albian and Cenomanian, the Earth underwent profound climatic and oceanographic changes that were recorded in sedimentary successions on a global scale. Carbon isotope records spanning this time interval have been established in the western Tethys, eastern Pacific and North Atlantic Oceans, but not yet in the eastern Tethys Ocean. In this paper, we present biostratigraphic, chemostratigraphic and cyclostratigraphic characteristics of the uppermost Albian–lowermost Cenomanian in an eastern Tethyan section (Youxia, southern Tibet). Based on calcareous nannofossil biozones and the bulk rock δ13C curve, the Albian-Cenomanian boundary interval (ACBI) was identified and correlated to the western Tethys and Atlantic Oceans. In the Youxia section, δ13C values range from approximately 0‰ to +1.3‰ (−0.03‰ to +1.31‰). Four subevents (a, b, c and d) were distinguished in the ACBI carbon isotope curve via correlation with other sections. Based on a spectral analysis of the carbonate content, we recognized Milankovitch short eccentricity (~100 kyr) and precession (22.2 kyr) cycles, suggesting that orbital variations modulated depositional processes. The duration of the ACBI was estimated at ~311 kyr, while OAE 1d lasted for ~233 kyr in the eastern Tethys Ocean, consistent with the duration calculated from Atlantic Ocean records.

The calcareous nannofossil Ceratolithus acutus (= C. armatus) is an important species associated with the final flooding that ended the Messinian Salinity Crisis in the Mediterranean. We emphasize its robust identifying features and stratigraphic value in the global ocean. This species is particularly useful in recognising and constraining the Messinian–Zanclean boundary in the Mediterranean, as evidenced by reports from 75 localities and 20 references in addition to our own papers. Our emphasis is prompted by the assessment of Stoica et al. (2016) that Ceratolithus acutus is a “dubious” species with its lowest occurrence an “unreliable” biostratigraphic event. Such assessments by non-specialists, especially when “supported” by selective referencing of the literature warrant an explanation.

This study presents detailed foraminiferal, ostracod, and calcareous nannofossil analyses of five Middle Miocene sections located in the Central Paratethyan realm, namely in Poland, Romania and the Republic of Moldova. Based on foraminiferal distribution, five biostratigraphically important assemblages (labelled A-E) are distinguished. Foraminifera data combined with ostracoda and nannofossil evidence allowed correlation between the studied sections, and a comparison with the deposits of similar age from the Transylvanian, Vienna and Pannonian basins, as well as with the Transcarpathian regions. The micropaleontological record across the Badenian-Sarmatian boundary interval is also presented.

The mid Cretaceous is characterized by high eustatic sea-levels with widespread oxic conditions that made possible the occurrence of globally correlated Oceanic Red Beds. However, very often, these eustatic signals have been overprinted by local tectonics, which in turn resulted in Lower Cretaceous closed and anoxic basins, as in the Eastern Carpathians. There, the black shale to red bed transition occurs in the latest Albian up to the early Cenomanian. Although earlier studies discussed the large-scale basin configuration, no detailed petrography and sedimentology study has been performed in the Eastern Carpathians. This paper describes the Hauterivian to Turonian lithofacies and interprets the depositional settings based on their sedimentological features. The studied sections crop out only in tectonic half windows of the Eastern Carpathians, part of the Vrancea Nappe. The lithofacies comprises black shales interbedded with siderites and sandstones, calcarenites, marls, radiolarites and red shales. The siliciclastic muddy lithofacies in general reflects accumulation by suspension settling of pelagites and hemipelagites in anoxic (black shale) to dysoxic (dark gray and gray to green shales) and oxic (red shales) conditions. The radiolarites alternate with siliceous shales and are considered as evidence of climate changes. The sandstones represent mostly low and high-density turbidite currents in deep-marine lobes, as well as channel/levee systems. The source area is an eastern one, e.g., the Eastern Carpathians Foreland, given the abundance of low grade metamorphic clasts. The Hauterivian – lower Albian sediments are interpreted as deep-marine, linear and multiple sourced mud dominated systems deposited in a mainly anoxic to dysoxic basin. The anoxic conditions existed in the early to late Albian, but sedimentation changed to a higher energy mud/sand-dominated submarine channels and levees. This coarsening upwards tendency is interpreted as the effect of the Aptian to Albian compressional tectonics of the Carpathians. The deepening of the Moldavide Basin from the Cenomanian is most probably linked to a significant sea-level rise.

International audience; The work poses the question about the impact of inherited structures in the Black Sea back-arc basin (BAB) tectonic evolution. The new structural analysis of the Northern Dobrogea (ND) and the Crimean Mountains (CM) shows that the origins of structural patterns of both regions are in close relationship with deep faults/or fault zones. The comparative analyses of structures, of tectonic stages and their duration allow us to better understand the connections in time and space between the ND and the CM, against the back-ground of the long-living subduction. In particular during: (1) the Cimmerian orogeny; (2) the opening of the BS and (3) the inversion of the BS during the Cenozoic shortening.

International audience; The Zambezi Delta draining the Southern African Plateau and the southern part of the East African Rift is one of a the largest delta of Africa with a long-lasting history starting during Early Cretaceous with more than 12 km of sediments deposited. The Zambezi Delta is therefore a unique archive of the past topographic evolution of southern and eastern Africa and their related deformations, but also of the climate changes, global and regional (consequences of local topographic growths). Understanding this archive supposes to get a high-resolution dating of the sediments. Our two objectives are here (1) to construct an age model of the Zambezi Cenozoic delta using a combination of biostratigraphy, orbital stratigraphy and sequence stratigraphy and (2) to determine the palaeoprecipitation variations of the Zambezi catchment from the Oligocene to present day in a known tectonic framework. The Neogene sequences were dated at high-resolution assuming that the third order sequences are of eustatic origin and record long-term eccentricity cycles. The sequences were correlated in ages on the calculated Earth orbital solutions of Laskar for the time intervals provided by the biostratigraphy (nannofossils, planktonic foraminifers). The palaeoprecipitation record was based on the definition of a humidity index based on pollen analysis and associated botanical associations. The late Oligocene was a quite wet period getting dryer in the uppermost Chattian. The base Tortonian (11 Ma) was a humid period. The Messinian was a dry period with a slight increase of the humidity during the Zanclean and a sharp increase around the Zanclean-Piacenzian boundary. The Zambezi Delta has recorded the uplifts of the Southern African Plateau (around 85 Ma and around 25 Ma) and those of the southward migration of the East African Rift (since 5.5 Ma).

International audience; Sediments deposited after the peak of the Messinian Salinity Crisis (MSC) in the Apennine foredeep of Italy embody a topic debated on both chronostratigraphic and palaeoenvironmental grounds. We performed micropalaeontological (calcareous nannofossil and dinoflagellate cyst) analyses on four stratigraphic sections (Monticino, Civitella del Tronto, Fonte dei Pulcini, Fonte la Casa) and reused those from Maccarone. All sections belong to the p-ev 2 Formation that includes the Colombacci deposits, usually considered emblematic of the Lago Mare in the area. Marine microfossils recorded in previous studies have often been neglected or considered reworked and hence discarded. We propose the occurrence of at least four marine inflows between 5.36 and 5.33 Ma, the first of which is reflected in the Apennine foredeep by marine dinoflagellates that are then replaced by Paratethyan (brackish) ones. Paratethyan species occupied favourable environments during intervals separating marine inflows while the marine species survived elsewhere. From this perspective, the Apennine foredeep was an isolated perched basin during most of the peak of 2 the MSC (5.60–5.36 Ma), and was progressively and repeatedly invaded by marine waters overflowing a palaeo-sill before the beginning of the Zanclean (5.33 Ma) which itself reflects a continuing eustatic rise. The Gargano Peninsula and, offshore, the present-day Pelagosa sill may be regarded as the remnants of such a Messinian sill. This interpretation provides new possibilities for ecostratigraphically correlating the sections with Lago Mare biofacies, the deposition of which unquestionably started prior to the deposition of Colombacci sediments and continued just into the earliest Zanclean. The results of this study show that the Lago Mare facies cannot be restricted to a single brackish palaeoenvironment but included competing marine and brackish waters controlled by geographic and chronological factors. Deposits overlying the unconformity separating the regional p-ev 1 and p-ev 2 formations are considered to represent the first marine incursion into the Apennine foredeep. These results allow us to refine the palaeogeographic reconstruction of the Apennine foredeep during the peak of the MSC. Although this basin was deep, its history during the peak of the MSC did not parallel that of the central Mediterranean basins.

The Buzau Land Geopark, located in SE Romania, in the outer part of the Eastern Carpathians, encloses many geological and palaeontological sites of high scientific value, including unique geological phenomena. The amber deposits, the salt caves, the mud volcanoes, the mineral springs and the Neogene fossiliferous sites, along with the impressive beautiful geological landforms and landscapes represent a significant geoheritage and an attraction for worldwide tourists. The geological and palaeontological heritage of The Buzau Land Geopark may be seen also as a strong supporter for Earth Science education, and one of the best policies to promote geoconservation. So far, however, only a few geological and palaeontological sites are protected; for the other sites, the significant geodiversity indicates that they have a good potential to become protected areas of national interest. The future actions that will be taken as results of the researches in The Buzau Land Geopark need to support geoconservation, leading also to the development of the entire region.

International audience; New investigations in the Neogene Boudinar basin (Morocco) provide new information about the Messinian Salinity Crisis (MSC) and Zanclean reflooding in the southern part of the Alboran realm (westernmost Mediterranean). Based on a new field, sedimentological and palaeontological analyses, the age and the geometry of both the Messinian erosional surface (MES) and the overlying deposits have been determined. The MES is of late Messinian age and was emplaced in subaerial settings. In the Boudinar basin, a maximum of 200 m of Miocene sediments was eroded, including late Messinian gypsum blocks. The original geometry of the MES is preserved only when it is overlain by late Messinian continental deposits, conglomeratic alluvial fans or lacustrine marly sediments. These sediments are interpreted as indicators of the sea-level fall during the MSC. Elsewhere in the basin, the contact between late Messinian and early Pliocene deposits is a low-angle dipping, smooth surface that corresponds to the early Pliocene transgression surface that subsequently re-shaped the regressive MES. The early Pliocene deposits are characterized by: (i) their onlap onto either the basement of the Rif chain or the late Miocene deposits; (ii) lagoonal deposits at the base to offshore marls and sands at the top (earliest Pliocene; 5.33–5.04 Ma interval; foraminifer zone PL1); (iii) marine recovery occurring in the 5.32–5.26 Ma interval; and (iv) the change from lagoonal to offshore environments occurring within deposits tens of metres thick. This information indicates that at least the end of the reflooding period was progressive, not catastrophic as previously thought.

Investigations of calcareous nannoplankton assemblages including species richness and abundance data were performed across the K–Pg boundary interval at Agost (SE Spain), between − 100 cm and + 100 cm, below and, respectively, above the boundary, at a considerable high resolution averaging 2 cm. From a total of 98 species of the Upper Maastrichtian, only 13 survived mass extinction, while the rest of the 86% vanished in the K–Pg fallout layer. A slight progressive decline in species richness and abundance was observed toward the top of the Maastrichtian, where mixed assemblages, consisting of both cold-water taxa and typical Tethyan ones are present. Four successive acme events were observed, i.e. Markalius inversus and the calcareous dinoflagellate genus Thoracosphaera starting from the base of the Paleocene, followed by those of Braarudosphaera bigelowii and Neobiscutum parvulum. The most prominent acme intervals belong to Thoracosphaera spp. and B. bigelowii, opportunistic taxa, for which the survival strategy may be linked to their capability to encyst and survive severe environmental deterioration. At the upper part of the studied succession, calcareous nannoplankton assemblages are already dominated by survivor species, as well as incoming ones, showing an early pioneer calcareous nannoplankton ecosystems about 35–40 kyr after the K–Pg boundary. Correlation between the calcareous nannoplankton assemblage fluctuation, including species richness and abundance, and the paleoenvironmental changes, such as the eustatic and climatic modifications, are also discussed.

The Pontides forming the south-western continental margin of the Black Sea consist of two tectonic units, the Istanbul Zone in the west, and the Sakarya Zone in the central and eastern parts. The Sinop Basin in the Sakarya Zone is filled, from base to top, by Hauterivian to Albian turbidites, Cenomanian–Turonian red pelagic sediments, Turonian–Campanian magmatic-arc and related deposits, and by the uppermost Campanian to middle Eocene post-magmatic units developed on the southern passive margin of the Black Sea. Based on nannofossil, dinoflagellate, Foraminifera and Radiolaria data we describe the Kapanbogazi Formation, a Cenomanian–Turonian unit in the Sinop Basin, represented by red calcareous/siliceous pelagic shales, limestones and cherts passing gradually from the Albian black shales. These sediments possibly represent deepest depositional conditions of the basin during the Cenomanian–Turonian interval and also reflect the transition from an anoxic to an oxic palaeoenvironmental setting. The Istanbul Zone to the west was emerged during the deposition of the Kapanbogazi Formation in the Sakarya Zone. In the Pontides, red pelagic sediments were deposited at different times during the Cenomanian–Maastrichtian interval. Because the Kapanbogazi Formation was deposited only in the Sakarya Zone and because it is present in limited outcrops due to structural reorganization and thick overlying volcanoclastic pile, most previous authors assumed Cenomanian–Turonian hiatus. Herein we describe detailed palaeontological data from this unit and discuss their importance to the interpretation of depositional history and tectonics of the Black Sea region, as well as climatic and eustatic implications.

Propagation processes of plate‐scale faults through continental lithosphere are poorly documented. The North Anatolian Fault (NAF) is a continental right‐lateral transform with striking evidence for propagation processes in the Marmara Sea pull‐apart region. Earlier work (Armijo et al., 1999, https://doi-org.ezlibproxy1.ntu.edu.sg/10.1130/0091‐7613(1999)0272.3.CO;2) suggests that in the Dardanelles, where the principal, northern branch of that fault (NNAF) enters into the Aegean: (1) a fold‐thrust system has progressively developed above the NNAF fault tip, at the WSW corner of the Marmara Sea pull‐apart. The main anticline formed there was sheared and its SW half laterally offset by ~70 km to the SW; (2) the timing of structure development appears correlated with sea level changes associated with the Messinian Salinity Crisis. Our new description of the Dardanelles (or Ganos‐Gelibolu) fold‐thrust system is based on structural mapping, field observations, and calcareous nannoplankton analyses to date key sedimentary units. Our results provide tight constraints on the main pulse of folding associated with propagation of the tip of the NNAF: it took place in the late Miocene to earliest Pliocene (5.60 to 5.04 Ma), before deposition of undeformed Pliocene marine sediments. The folding is mostly coeval with the Messinian Salinity Crisis and accommodated several kilometers of shortening at the fault tip. After full propagation of the NNAF up to the surface, the folded structure was sheared and right laterally offset, with an average 14 mm/year of slip rate during the past ~5 Myrs. A reconstruction of tectonic evolution suggests a flower structure nucleating and taking root at the tip of the fault. Published version

The studied Cernatu Valley section is situated in the central part of the Eastern Carpathians (Romania) and spans the interval covered pro parte by the NC10a (=CC9b) calcareous nannofossil Subzone, as well as the Plectorecurvoides alternans and Haplophragmoides falcatosuturalis agglutinated foraminiferal zones. The presence, within the lower part of the section, of the ammonite Stoliczkaia notha indicates a late Albian age, but the section possibly extends to within the Albian-Cenomanian boundary interval, based on the agglutinated foraminiferal assemblages. The deposits are grey to blackish and green shales that are followed by red shales interbedded with couplets of grey to blackish and green shales. The benthic foraminifers suggest a deep-marine depositional setting, probably lower bathyal or even abyssal, at around 2500 m depth. The deposition was probably near but above the Calcium Compensation Depth (CCD), as very scarce nannofloras and macrofaunas are present. The δ13Corg values vary throughout the section between −25.30‰ and −24.01‰. Within the upper Albian, a positive organic δ13Corg excursion with increases of 1.3‰, up to −24.01‰, is recorded. This positive excursion has been tentatively interpreted as a regional expression of the Oceanic Anoxic Event OAE1d in the Moldavian Trough of the Eastern Carpathian basin. The upper part of the section, belonging to the Haplophragmoides falcatosuturalis agglutinated foraminiferal Zone, contains a weak positive δ13Corg excursion marked by an increase in values of about 0.5‰, which is assumed to represent late phases of the Albian-Cenomanian boundary Event. Towards the top of the section, consisting mainly of red shales, calcareous foraminifera also occur, together with more consistent nannofossil assemblages. This biotic change possibly mirrored an alteration of the palaeoenvironment, which shifted from an anoxic/dysoxic setting towards an oxic one. This change is possibly linked to climatic fluctuation, i.e., the onset of a warm and humid climate mode. The intense tectonic activity that took place within the Eastern Carpathians during mid-Cretaceous times could also have been responsible for the environmental changes by modifying the circulation pattern in the Moldavian trough from a restricted circulation to a more open one.

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The Organya Basin, south–central Spanish Pyrenees, developed as a marginal depocenter during a rapid extensional phase of anticlockwise rotation of the Iberian plate. As a result of increased subsidence, an important change in sedimentation occurred from the late Barremian to the Aptian leading to unusually high sediment accumulation rates. Approximately 1000 m of hemipelagic marls and limestones accumulated during this time interval. Here we studied the basal 85 m of the hemipelagic facies of the El Pui section, Organya Basin, that are characterized by alternating 15 cm – ∼3 m thick beds of limestone and marls. Geochemical analyses indicate high total inorganic carbon (TIC) values (average 70%) suggesting enhanced CaCO3 production and deposition. SEM analyses of the samples indicate high abundance of calcareous nannofossils, which together with the absence of shallow water taxa characteristic of the Urgonian Carbonate platform of Organya, and the lack of sedimentary facies attributable to carbonate platform components point to nannofossils as the main source for the elevated TIC. Organic-rich levels (total organic carbon (TOC) up to 1.74%) concurrent with positive excursions up to 2‰ in δ13Corg, imply enhanced preservation of organic matter (OM) in the basin. In addition, pronounced peaks of δ13Corg higher than the global average suggest superimposed local factors related to intensified 12C removal due to primary productivity. Biomarker analyses and the δ13Corg profile suggest an autochthonous origin of the OM from phytoplankton and possible additional contributions from microbial communities. X-ray diffraction (XRD) results attest for sustained terrestrial fluxes as the source of nutrients to the basin because of a 30% average non-carbonate bulk mineral content in the sediment. The non-carbonate fraction is dominated by quartz (average, 14%) whereas the clay mineral assemblages are characterized by high illite content (>73 relative%) with minor concentrations of kaolinite (

The impressive 2000 m thick conglomerates of the Bucegi Formation exposed in the southernmost part of the Eastern Carpathians were interpreted initially as large alluvial fans, and later suggested to be deposited as deepwater submarine-slope deposits. However, the routing system of the coarse sediment transfer from the source area to the deepwater slope (source-to-sink analysis) has not been explained and the mechanisms involved in the shelf sediment storage and bypass onto the slope have not been discussed. The present research on the Albian Bucegi Formation has provided the following new insights on their source-to-sink aspect: (1) that the Upper Member of the Bucegi Formation, with its frequent channelized and sheet like fine conglomerates and sandstones, contrasts greatly with the Middle and Lower members of deepwater slope and basin-floor origin. The Upper Member is interpreted as fluvial and shallow-marine deposits that were temporarily stored and reworked on a ‘shelf’, albeit a narrow one, bridging the area between the deforming hinterland and the deepwater slope deposits; (2) the Upper and Middle members are genetically linked and developed through the basinward migration of a large-scale (hundreds of metres in amplitude) clinoform with relative flat-lying topsets and slightly steeper (few degrees), coarser grained slopes that built out to the south and southeast; a configuration that is common along continental margins and also generally along all types of deepwater basin margins; (3) the Middle Member contains a range of submarine, sediment density flows that vary from high-density, mobile debris flows to lower-density sandy turbidites. The sediment textures (sorted grain populations) inherited from the shelf ‘sorting factory’ can to some extent still be recognised in the slope stratigraphy; and (4) the large (10–20 m diameter) carbonate and metamorphic olistoliths that are ubiquitous on the shelf and (to a lesser extent) slope, reflect the steep gradients and very active tectonic setting of the fractured and thrusted hinterland, from which these outsized blocks were transported onto the adjacent shelf. The now-proposed, narrow shelf platform of the Albian Bucegi basin margin thus functioned to temporarily store sands and gravels, to distinctly sort some of this sediment, and to eventually bypass both sorted and new flood-generated, unsorted materials onto the slope. Compared with other basin margins, this Albian Bucegi margin was extremely coarse grained because of its proximity to the actively deforming mountain range, to a fractured basement that produced more gravel than sand, to the great sediment flux from steep short rivers, and to the narrowness (10–20 km) of the shelf.

International audience; New data from the Neogene Boudinar and Arbaa Taourirt basins (northeastern Morocco) provide constraints on the late Miocene evolution of the North Rifian Corridor. The chronostratigraphy of these basins is clarified on the basis of biostratigraphic (planktonic foraminifers, calcareous nannoplankton) and radio-isotope ages. Marine sedimentation in the Boudinar Basin began during the early Tortonian at ~ 10 Ma and persisted until the late-early Messinian at ~ 6.1 Ma. In the Arbaa Taourirt basin, it occurred between the late Tortonian and the earliest Messinian. Paleoenvironmental data (benthic foraminifera and pollen grains) record a major drowning in association with extensive tectonism in the Boudinar basin during the early Messinian (~ 7.2 Ma). Synchronously, there was a major sedimentological change in the Arbaa Taourirt basin with progradation of conglomerates and sandstones over late Tortonian marls. Large-scale cross-bedded sandstones indicate paleo-currents flowing from the Atlantic Ocean toward the Mediterranean Sea. During the late-early Messinian, a shallowing trend occurred, culminating with the progradation of reefal carbonates. Our findings indicate that the North Rifian Corridor opened at ~ 7.2 Ma ensuring Atlantic-Mediterranean connections. The Corridor was progressively restricted during the late-early Messinian with complete closure by ~ 6.1 Ma. The results of this study thus question existing hypotheses for the timing and nature of Atlantic-Mediterranean connections during the late Messinian.

The Cretaceous oceanic red bed (CORB) is a newly opened window on global oceanic and climate changes during the Cretaceous greenhouse world. As a result of the International Geoscience Programmes 463, 494 and 555 (2002–2010), CORBs have been documented in many places by numerous publications. The principle goal of this paper is to summarize scientific advances on CORBs including chronostratigraphy, sedimentology, mineralogy, elemental and isotopic geochemistry, and their relationship to oceanic anoxic events (OAEs), palaeoclimate and palaeoceanography. We propose a new geochemical classification of the CORBs using CaO, Al 2 O 3 and SiO 2 values, which lithologically refer to marly, clayey, and cherty CORBs respectively. Detailed mineralogical studies indicate that hematite, goethite and Mn 2 + -bearing calcite are the minerals imparting the red color of CORBs. Hematite clusters of several to tens of nanometers in the calcite structure are the main cause of the red coloring of limestones, and the Mn 2 + -bearing calcite gives additional red color. Goethite was thought to form originally with hematite, and was subsequently transformed to hematite during late diagenesis. Chronostratigraphic data allow the distinction of two groups of CORBs by their durations. Short-term CORBs are generally less than 1 myr in duration, and seem to be on the scale of Milankovitch cycles. During the deposition of Cretaceous reddish intervals from ODP cores 1049 and 1050, low primary productivity and relatively high surface temperature resulted in low organic carbon flux into the sediments which reduced oxygen demand and produced oxidizing early diagenetic conditions. In such an oxic environment, iron oxides formed imparting the reddish color. The long-term CORBs' depositional events lasted longer than 4 myr, and may be a possible consequence of the OAEs. Enhanced amounts of organic carbon and pyrite burial during and after the OAEs would have resulted in a large and abrupt fall in atmospheric CO 2 concentration, which probably induced significant global climatic cooling during and after the OAEs. Global cooling would have enhanced formation of cold deep water, increasing its oxidizing capacity due to the greater content of dissolved oxygen and would promote formation of oceanic red beds. Sedimentological, mineralogical and geochemical data indicate that CORBs were deposited under highly oxic, oligotrophic conditions probably at a low sedimentation rate. The Cretaceous red and white limestones from Italy have similar compositions of terrestrial input-sensitive elements (Al, Ti, K, Mg, Rb, Zr), higher contents of Fe 2 O 3 , and depleted redox-sensitive elements (V, Cr, Ni, and U) and micronutrient elements Cu, Zn, indicating similar provenance sources but red limestones were deposited under more oxic conditions at the sediment–water interface than white limestones. The Cretaceous red shales such as those from the North Atlantic and Tibet have similar mineralogy and geochemistry as the Late Cenozoic red clays in the Pacific Ocean and the environment where both are formed was well-oxidizing at a very low sedimentation rate. We compiled seventeen published stratigraphic examples of Phanerozoic oceanic red beds including the Late Cenozoic red clays in the Pacific. Different hypotheses explain the origin of red pigmentation of limestones and shales including (1) detrital origin of iron derived from continental weathering; (2)iron-bacterial mediation at the time of sedimentation; and (3) iron oxidation in oligotrophic, highly oxic environment. Additional research on Phanerozoic oceanic red beds is needed in order to better document their origin and palaeoceanographic and palaeoclimatic significance.

Lower Cretaceous deposits of the Tarcau Nappe, central part of the Eastern Carpathians, were studied, aiming to point out their lithofacies and to reconstruct the changes in depositional palaeoenvironment of those times. The investigated deposits extend within the NC5-NC10 calcareous nannoplankton biozones, covering the Late Barremian–Late Albian. Based on sedimentological, petrographical and geochemical features, ten lithofacies were identified, grouped in three categories, such as shaly, siliciclastic and carbonate. The shaly lithofacies consist of black and grey shales, as well as carbonate shales yielding an average of organic matter content around 3%. The organic matter and pigments of iron, such as hydrotroillite are responsible for the occurrence of the black colour. Preservation of the organic matter is due to anoxic environments induced by reduced current flow and intensified water density stratification. The siliciclastic lithofacies are mainly composed of quartz arenites, quartzwackes, and subordinately sublitharenites and lithic graywackes. The carbonate lithofacies include predominantly marls and siderites, originating by diagenetical processes of the shaly lithofacies, and subordinately calcarenites with terrigenous material and sponge spicules. The petrography and geochemistry indicate that the main sources of the sandy detrital material are the basement and sedimentary cover of the Central (Scythian) and East European platforms. The black and grey shale deposition, in the Barremian–Late Aptian interval, reflects suspension settling of the hemipelagic and pelagic material. Thin sandy beds, with parallel lamination and current ripples, suggest low-density turbidity currents, while the Albian thick sandy beds with massive or normal grading and parallel lamination are interpreted as high-density turbidity currents or even sandy debris flows. The shaly depositional intervals are linked to the basinal plain, while the sandy dominated sequences are associated with turbiditic lobes.

Detailed lithological and micropaleontological studies were performed on several cores from the Romanian Black Sea shelf, located in front of the Danube Delta, in front of the Razelm–Sinoe lagoonal complex, close to the Eforie beach, as well as on the Romanian inner shelf. All the studied cores are situated at a water depth varying between 12 m and 67 m. The purpose of the investigations was to reveal Upper Holocene lithological changes and the associated calcareous nannoplankton fluctuations in a very shallow marine setting such as the Romanian Black Sea inner shelf. The youngest Holocene unit or “Shallow Unit” is composed of alternating sequences of mud, silt, clay and coquina layers, containing marine mollusc faunas. The upper part of the Shallow Unit contains blooms of the nannoplankton species Emiliania huxleyi , while its lower part yields, besides common E . huxleyi , rare specimens of Braarudosphaera bigelowii . The Shallow Unit overlies a “shell hash layer”, mainly made by coquinas, containing mixing marine and brackish mollusc faunas. Towards the upper part of this level, monospecific assemblages with B . bigelowii were observed in a layer rich in carbonate acicular crystals. The Shallow Unit partly corresponds to the Unit 1 (finely laminated coccolith ooze) and Unit 2 (sapropelic sediments) of slope and basinal settings of the Black Sea. The layer rich in carbonate acicular crystals could be a shallower equivalent of the oldest layer of aragonite bands placed at the lower part of the Unit 2 in deep parts of the Black Sea. In the analyzed cores, the oldest lithological unit (Unit 3, the muddy clay sediments deposited in a brackish to freshwater environment) is characterized by the deposition of green-yellowish clay devoid of any Holocene calcareous nannoplankton species and containing brackish mollusc faunas. Based on nannofloral fluctuations, an increasing salinity from the base towards the upper part of the Shallow Unit may be supposed, together with the progressive establishment of a stable marine setting, similar to today.

This study focused on the Cretaceous black shale successions, followed by red shales that crop out at the outer regions of the Romanian Carpathians, in the Moldavids. The oldest parts of the black shale units deposited in an abyssal plain during Late Valanginian–Late Barremian time; they are mainly characterized by hemipelagic and pelagic muddy siliciclastic rocks and carbonates, commonly intercalated with fine-grained turbidites. During the sedimentation of the middle part of the black shale units in the Late Barremian–Early Albian interval, the depth of the basin increased, as the carbonate hemipelagic sedimentation was replaced by a mainly siliceous one. Only a few thin turbidite intercalations are present. The youngest part (Albian pro parte) of the black shale units is characterized by a turbiditic sedimentation, with mainly sandy sequences of middle and lower deep-water fans. We may assume that the depth of the basin continuously decreased. The presence of authigenic glauconite in the Albian sandstones suggests a palaeoenvironmental change, linked to the occurrence of oxygenated turbidity current circulation. A significant shift in the sedimentation regime in the Eastern Carpathian Moldavids took place in the Late Albian, when Cretaceous Oceanic Red Beds (CORB) occurred. This type of sedimentation lasted up to the Coniacian. The lower part of the CORBs that contains radiolarites intercalated with variegated shales, pyroclastic tuffs and thin sandstones is interpreted as a hemipelagic and pelagic sedimentation in the abyssal plain environment, where rarely turbidites occurred. Upwards, there are mainly burrowed variegated red and green shales. The youngest parts of CORBs are characterized by increased thickness and frequency of the turbidites. While the main part of the CORB is carbonate free or has very low carbonate content, the upper part of these strata becomes rich in marl and mudstone strata, indicating a decrease of the basin-depth. The accumulation of black shales in the Eastern Carpathians during the Late Valanginian–Late Albian interval is linked to the existence of a small, silled basin of the Moldavian Trough, in which restricted circulation led to the density stratification of the water column, resulting in the deposition of anoxic Lower Cretaceous sediments (i.e., the black shales). Because of the tectonic deformation that took place within the Lower–Upper Cretaceous boundary interval, the restricted circulation had changed to an open circulation regime in the Moldavian Trough. Hence, the anoxic regime was progressively replaced by an oxic one, across the Albian–Cenomanian boundary interval. The beginning and the end of the CORBs in the Moldavid units depend thus on various palaeogeographic and palaeoenvironmental settings, and it was controlled by the regional tectonic activity.

This paper presents the lithological and biostratigraphical (mainly based on calcareous nannofossils) record of the marine sediments which crop out in the NW and SE Haţeg regions. Upper Cretaceous marine deposition starts in these two regions in the Early Cenomanian (both in the CC9 calcareous nannofossil zone, and within UC1–UC2 biozones, respectively). In NW Haţeg, a hemipelagic sequence composed of red shales and marlstones, followed by white marlstones, probably associated with a deep-water paleoenvironment, marked the beginning of Upper Cretaceous marine sedimentation. In the SE, marine deposition started with sandstones and calcarenites, interlayered with Actaeonella and Ytruvia coquina, indicating an infralittoral paleoenvironment. From the Cenomanian up to the Coniacian, the marine setting becomes progressively shallower in the two Upper Cretaceous marine depositional Haţeg areas; this change is marked by the occurrence of outer shelf deposits in the NW and inner shelf sediments up to infralittoral ones in the SE. These deposits are followed by lower Santonian–upper Campanian turbidites in the NW, and by Lower Santonian–Campanian pro parte red marlstones and Upper Campanian turbidites, in the SE. The marine sedimentation ends, in NW Haţeg, with distal turbidites, Late Campanian in age (placed in the CC22 calcareous nannofossil zone, in the UC15d subzone respectively, slightly above the first occurrence of the nannofossil Uniplanarius trifidus ). Towards the end of the Campanian, conglomerates and sandstones with Actaeonella and Ytruvia coquina, yielding reworked nannofloras (including Late Campanian taxa), occur in SE Haţeg. Associated with the paroxysmal Laramian tectonic phase, continental deposition started, probably within the Campanian/Maastrichtian boundary interval, both in the NW and SE parts of the Haţeg region. During the Late Cretaceous interval, different paleoenvironmental settings may be distinguished in the NW Haţeg (where a deep marine basin developed for most of the Early Cenomanian up to the Late Campanian interval), and in the SE Haţeg (characterised by an outer oscillating basin with an episodic shallow-water deposition in the same interval). Despite the various backgrounds of the two regions, some common regional events, such as the Early–Middle Cenomanian and the Early Santonian–Early Late Campanian sea level highstand, as well as the Late Cenomanian–Coniacian sea-level lowstand were recognised in both investigated areas.

This study presents carbon and oxygen isotope fluctuations identified in marine red marlstones and claystones of the Fizesti Formation from the SE Haţeg area (Southern Carpathians, Romania). Biostratigraphy based on calcareous nannoplankton allow the identification of nannofossil standard zones and subzones CC16–CC17 up to CC20, and respectively UC11c up to UC15b, indicating that the investigated deposits are latest Coniacian–late Early Campanian in age. Throughout the studied succession, δ13C values fluctuate between 1.4‰ and 2.65‰, while δ18O values are between − 3‰ and − 4‰. In the middle Santonian (within the UC12 calcareous nannofossil zone), we found a slight positive carbon isotope excursion, with values increasing by 0.3‰, up to a value of 2.44‰, which we assume to represent the regional expression of the Horseshoe Bay Event, originally recognized in the English Chalk. In the uppermost Santonian, just below the first occurrence of the crinoid Marsupites testudinarius (within the UC13 calcareous nannofossil zone), we recorded a δ13C increase, from 2.38‰ up to 2.63‰, correlative with the Hawks Brow Event, firstly described in UK. The most significant δ13C increase identified by us, up to 2.63‰, is coincident with the last occurrence of the crinoid Marsupites testudinarius (= the Santonian–Campanian boundary) and represents the regional expression of the worldwide distributed Santonian/Campanian Boundary Event. The Santonian–Campanian boundary is associated with a slight positive excursion for δ18O. In the lower part of the Campanian stage, δ13C values progressively decrease to around 1.5‰. A decrease of the water surface temperature in the region is suggested for the lower part of the Santonian, an assumption based on the significant shift to less negative values of δ18O and on the mixed (Tethyan and Boreal) character of the identified nannofloras. From the Santonian–Campanian boundary interval upwards, the temperatures were rising, leading to an arid and warm climate in the region. This climate mode continued probably into the Maastrichtian, when the Haţeg area became part of an island situated in the Northern Tethys Realm.

International audience; Outcrops, offshore wells, electric logs and seismic profiles from northern Tunisia provide an opportunity to decipher the Messinian Salinity Crisis in the Strait of Sicily. Messinian deposits (including gypsum beds) near the Tellian Range reveal two successive subaerial erosional surfaces overlain by breccias and marine Zanclean clays, respectively. In the Gulf of Tunis, Messinian thick evaporites (mostly halite) are strongly eroded by a fluvial canyon infilled with Zanclean clays. The first erosional phase is referred to the intra-Messinian tectonic phase and is analogous to that found in Sicily. The second phase corresponds to the Messinian Erosional Surface that postdates the marginal evaporites, to which the entire Sicilian evaporitic series must refer. The Western and Eastern Mediterranean basins were separated during deposition of the central evaporites.

Fluctuation in calpionellid, foraminiferal, and nannofossil diversity and abundance are documented in two successions located in the eastern part of the Upper Jurassic–Lower Cretaceous carbonate platform of the Southern Carpathian area, Romania. The lower part of the studied sections consists of upper Tithonian–upper Berriasian bioclastic limestones. This age is supported by the presence of the calpionellid assemblages assigned to the Crassicollaria, Calpionella, and Calpionellopsis Zones. Based on biostratigraphical data, a gap was identified within the uppermost Berriasian–base of the upper Valanginian (the interval encompasses the Boissieri, Pertransiensis, Campylotoxum, and lower part of the Verrucosum ammonite Zones). Hence, the upper Tithonian–upper Berriasian bioclastic limestones are overlain by upper Valanginian–lower Hauterivian pelagic limestones (the interval covered by the NK3B and NC4A nannofossil Subzones). A detailed qualitative and semiquantitative analysis of the nannoflora was carried out over this interval. To estimate the surface water fertility conditions, the nannoplankton-based nutrient index (NI) was calculated. The fluctuation pattern of NI allow us to recognize four phases in the investigated interval, as follows: (1) phase I (covering the lower part of the NK3B nannofossil Subzone and the upper part of the Verrucosum ammonite Zone, respectively) is characterized by low values of the NI (below 20%), by the dominance of the genus Nannoconus in the nannofloral assemblages (between 60–70%), and moderate abundance of Watznaueria barnesae (up to 23%), while the high-fertility nannofossils constitute a minor component of the assemblages; (2) phase II (placed in the NK3B nannofossil Subzone, extending from the top of Verrucosum ammonite Zone, up to the lower part of the Furcillata ammonite Zone) is characterized by increase of NI above 30%, a decrease of nannoconids (up to 50% at the top), while Watznaueria barnesae increases in abundance up to 27%. The fertility proxies (Diazomatolithus lehmanii, Zeugrhabdotus erectus, Discorhabdus rotatorius, and Biscutum constans) represent again a minor component of the recorded nannofloras (less than 7% in both sections), but they have an ascending trend; (3) phase III (which encompasses the boundary interval of the NK3B and NC4A nannofossil Subzones, corresponding to the upper part of the Furcillata ammonite Zone) contains higher NI values (over 35%, and up 52% towards the base of this phase), an abrupt nannoconid decrease (down to 20%), higher abundance of Watznaueria barnesae (over 30%), while the fertility nannofossils became an important nannofloral component, jointly amounting to almost 20%; (4) phase IV (identified within the NC4A Nannofossil Zone and corresponding to the boundary interval of the Furcillata and Radiatus ammonite Zones) is characterized by a decrease of NI to 25%, a recovery of the nannoconids up to 40%, a decline in abundance of Watznaueria barnesae to 25%, together with a pronounced drop of fertility taxa, which make together no more than 8%. We assume that maximum of eutrophication in the studied interval from the Southern Carpathians was in the Furcillata ammonite Zone. Notably, within the phases 2 and 3, the morphological changes identified in the benthic foraminiferal assemblages (the predominance of flattened morphologies, together with the presence of conical and trochospiral inflated forms), as well as the occurrence of the Zoophycos trace fossils and pyrite framboids, indicate dysaerobic conditions. In the Southern Carpathians, the late Valanginian–early Hauterivian biogeographical changes are coeval with the initiation of the carbonate platform drowning.