Search

International audience

International audience; During the Middle-Late Eocene, the Earth transitioned from a greenhouse to icehouse period. Within this period, a warming phase of 500 kyr called MECO (Middle Eocene Climatic Optimum) took place at the beginning of the Bartonian (from 40.5 Ma to 40 Ma - C18n). This event is characterized by a negative shift in the δ18O profile of benthic foraminifera associated with an increase of 4 to 6 °C in surface and deep ocean waters. The peak of the MECO is also characterized by a short δ13C negative excursion at 40.0 Myr during an overall increasing trend of δ13C. This positive trend of the δ13C curve appears to be related to an atmospheric increase in the pCO2, but the causes remains unclear.Unlike the oceanic domain, few datas exist for the characterization of the MECO in coastal areas. Additionally, important component of the climatic context, such as the seasonal gradient of temperature, remain unknown. To unravel these uncertainties, this work focuses on the nearshore Eocene sedimentary records of the Paris Basin, which presents an important and remarkably well preserved paleobiodiversity of marine mollusk shells. Previous studies have confirmed that the MECO event is well recorded in Bartonian sediments, but due to several uncertainties, its stratigraphic position remains to be specified. Here we present a composite section that spans a stratigraphic interval covering the middle Lutetian (falunière de Grignon outcrop) and the Bartonian (Horizon de Mont-Saint Martin Formation, le Guépelle section and the Sables de Cresnes Formation). Thus, we combine different proxies provided by 18O, 13C and ∆47 analyses of marine mollusk shells sampled in these sections in order to clarify the stratigraphic position of the MECO in the sedimentary succession of the Paris Basin and to constrain the climatic expression of this hyperthermal event in shallow marine environment. Isotopic analyses were performed on the shells of 3 Bartonian mollusks species: 2 bivalves represented by Bicorbula gallica and Crassostrea cucullaris and 1 gastropod represented by Torquesia sulcifera. Stable isotope (δ18O and δ13C) results both show a characteristic negative excursion at the end of the Sables du Guépelle formation, in the lower part of the Bartonian. Clumped isotope analyses were performed on some specimens of B. gallica and T. sulcifera in order to better constrain the composition of δ18Ow throughout the stratigraphic interval studied. These results indicate significant decreases in local δ18Ow over the lifetime of most individuals, interpreted as large infra-annual variations in salinity. Paleotemperatures calculated from the previously constrained δ18Ocarbonate increase by 4 to 10 °C during the MECO event , while the seasonal temperature variation decreases from 11-13 °C to 8 °C during the negative isotopic excursion of the end of the Sables du Guépelle formation.Based on these new results, we propose that the MECO is recorded in the top of the Sables du Guépelle formation marked by a warming period and a lower seasonal temperature gradient. These results lead to a better chimio-chronostratigraphic calibration of the Bartonian deposits of the Paris Basin.

L’Optimum Climatique de l’Eocène Moyen (MECO), événement hyperthermal rapide (50ka) et global de l’Eocène moyen (40Ma), est notamment caractérisé par une augmentation de la température des eaux de fond et de surface de 4 à 6°C en domaine océanique. Les causes de ce réchauffement demeurent inexpliquées mais il est associé à une augmentation de la pCO2 atmosphérique. Ces caractéristiques font du MECO un analogue du réchauffement actuel. Le MECO est bien documenté en milieu océanique, mais l’analyse des foraminifères océaniques ne permet d’obtenir que des données climatiques moyennées et ne permet pas un suivi à très haute résolution des variations pluriannuelles de températures et du gradient saisonnier de température. C’est pourquoi cette étude se focalise sur le Bassin de Paris, présentant (1) un enregistrement sédimentaire important et varié en domaine marin proximal à l’Eocène moyen et (2) une grande biodiversité et une qualité de préservation paléontologique remarquable. Des études ont montré que le MECO serait bien enregistré dans la stratigraphie du Bassin de Paris, à la base de l’Auversien et sur l’île de Wight, mais sa localisation exacte dans les archives sédimentaires reste à déterminer. Le but de cette étude est donc (1) de localiser précisément le MECO par une approche chimiostratigraphique (δ18O, δ13C) dans les dépôts littoraux du Bassin de Paris, (2) de déterminer les caractéristiques climatiques (T°moyenne annuelle et gradient saisonnier) de cet événement par l’analyse isotopique des coquilles de mollusques et (3) de déterminer la réponse sédimentaire associée à ce réchauffement en contexte de bassin intracratonique. Pour cela, nous menons une approche couplée terrain et laboratoire avec l’étude des affleurements et l’échantillonnage de coquilles mollusques dans les sables marins de l’Auversien, dans une zone allant de la région du Vexin au Tardenois. Les résultats préliminaires confirment l’enregistrement d’un réchauffement au sein de la formation des Sables d’Auvers, à la base de l’Auversien.

Alluvial plains are geomorphic, dynamics entities, which build up during floods by depositing overbank sediments but also through the displacement and abandonment of alluvial channels. Therefore, abandoned channels are widely recognized at the surface of alluvial plains, and that are filled with fine-grained sediment recording paleo-alluvial paths as well as paleo-environmental evolution. In this study, we investigate paleochannels of the "Petite-Seine", in the Bassée alluvial plain between Nogent-sur-Seine and Montereau-Fault-Yonne. About fifty hand auger boreholes were analyzed to study the changes associated with the Seine River migration. We find evidence for channel reactivation and multithreads activity during the studied periods. Radiocarbon dating allows précising the timing of these changes since the Neolithic, and suggest locally the impact of humans, perhaps through dredging. Finally, a first reconstitution of paleotemperatures using the bacterial tetraethers allowed restituting climatic variations associated with the evolution of the plain in the last 1800 years., Les plaines alluviales sont des entités dynamiques du point de vue géomorphologique. Elles se construisent par sédimentation lors des crues, générant aussi les déplacements et abandons des réseaux de rivières. On retrouve donc à la surface des plaines alluviales des chenaux abandonnés remplis de sédiments fins qui constituent non seulement des témoins des paléo-tracés fluviatiles mais aussi des archives paléo-environnementales. Dans cette étude, nous investiguons les paléo-chenaux de la Petite-Seine, dans la plaine alluviale de la Bassée entre Nogent-sur-Seine et Montereau-Fault-Yonne. Une cinquantaine de sondages mettent en évidence les changements du cours de la Seine d'un chenal à autre avec des évidences de réactivation et de fonctionnement suivant un mode anastomosé. Les datations radiocarbones permettent de préciser ce calendrier depuis le Néolithique, et peuvent localement suggérer l'action anthropique sous forme de curage. Enfin, une première reconstitution des paléo-températures par la méthode des tétraéthers bactériens permet de restituer les variations climatiques associées à l'évolution de la plaine sur les derniers 1800 ans.

Oxygen-isotope thermometry played a critical role in the rise of modern geochemistry and remains extensively used in (bio-)geoscience. Its theoretical foundations rest on the assumption that 18O/16O partitioning among water and carbonate minerals primarily reflects thermodynamic equilibrium. However, after decades of research, there is no consensus on the true equilibrium 18O/16O fractionation between calcite and water (18αcc/w). Here, we constrain the equilibrium relations linking temperature, 18αcc/w, and clumped isotopes (Δ47) based on the composition of extremely slow-growing calcites from Devils Hole and Laghetto Basso (Corchia Cave). Equilibrium 18αcc/w values are systematically ~1.5‰ greater than those in biogenic and synthetic calcite traditionally considered to approach oxygen-isotope equilibrium. We further demonstrate that subtle disequilibria also affect Δ47 in biogenic calcite. These observations provide evidence that most Earth-surface calcites fail to achieve isotopic equilibrium, highlighting the need to improve our quantitative understanding of non-equilibrium isotope fractionation effects instead of relying on phenomenological calibrations., Isotopic thermometry of carbonate minerals postulates that their composition reflects thermodynamic equilibrium constants. Here the authors constrain equilibrium relationships between temperature, 18O/16O and clumped isotopes and find that most natural calcites form out of isotopic equilibrium.

International audience; The objective of the Transform Source to Sink Project (TS2P) is to link the dynamics ofthe erosion of the West African Craton to the offshore sedimentary basins of the African marginof the Equatorial Atlantic at geological time scales. This margin, alternating transform andoblique segments from Guinea to Nigeria, shows a strong structural variability in the marginwidth, continental geology and relief, drainage networks and subsidence/accumulation patterns.We analyzed this system combining onshore geology and geomorphology as well asoffshore sub-surface data.For the Cenozoic, mapping and regional correlation of dated lateritic paleo-landscaperemnants allows us to reconstruct two physiographic configurations of West Africa. These geometriesshow that the present-day drainage organization stabilized by at least 29 Myrs ago(probably by 34 Myr) revealing the antiquity of the Senegambia, Niger and Volta catchmentstoward the Atlantic as well as of the marginal upwarp currently forming a continental divide.The drainage rearrangement that lead to this drainage organization was primarily enhanced bythe topographic growth of the Hoggar swell and was associated with a major stratigraphic turnoveralong the Equatorial margin. Elevation differences between paleo-landscape remnantsgive access to the spatial and temporal distribution of denudation for 3 time-increments since45 Myrs. From this, we estimate the volumes of sediments and associated lithologies exportedby the West African Craton toward different segments of the margin, taking into account thetype of eroded bedrock and the successive drainage reorganizations.For the Mesozoic, we produced paleogeographic maps at the scale of West Africa spanningthe continental domain and offshore basins since 200 Ma. Mapping spatial and temporaldistribution of domains either in erosion (sources) or in accumulation (sinks) document theimpact of the successive rifting of Central and Equatorial Atlantic on the physiography of thearea. We use low temperature thermochronology dating along three transects perpendicularto the margin (Guinea, Ivory Coast and Benin) to determine periods of maximum denudation.We compare these data to accumulation histories in passive margin basins and discusstheir stratigraphic expression according to the type of margin segment they are preserved in.

National audience; The objective of the Transform Source to Sink Project (TS2P)is to link the dynamics of the erosion of theWest African Craton tothe offshore sedimentary basins of the African margin of the EquatorialAtlantic at geological time scales. This margin, alternatingtransform and oblique segments from Guinea to Nigeria, shows astrong structural variability in the margin width, continental geologyand relief, drainage networks and subsidence/accumulationpatterns. We analyzed this system combining onshore geologyand geomorphology as well as offshore sub-surface data.For the Cenozoic, mapping and regional correlation of dated lateriticpaleo-landscape remnants allows us to reconstruct two physiographicconfigurations of West Africa. These geometries showthat the present-day drainage organization stabilized by at least29 Myrs ago (probably by 34 Myr) revealing the antiquity of theSenegambia, Niger and Volta catchments toward the Atlantic aswell as of the marginal upwarp currently forming a continentaldivide. The drainage rearrangement that lead to this drainageorganization was primarily enhanced by the topographic growthof the Hoggar swell and caused a major stratigraphic turnoveralong the Equatorial margin of West Africa. Elevation differencesbetween paleo-landscape remnants give access to the spatial andtemporal distribution of denudation for 3 time-increments since45 Myrs. From this, we estimate the volumes of sediments andassociated lithologies exported by the West African Craton towarddifferent segments of the margin, taking into account the type oferoded bedrock and the successive drainage reorganizations.For the Mesozoic, we produced paleogeographic maps at the scaleof West Africa spanning the continental domain and offshorebasins since 200 Ma. Mapping spatial and temporal distributionof domains either in erosion (sources) or in accumulation(sinks) document the impact of the successive rifting of Centraland Equatorial Atlantic on the physiography of the area. We uselow temperature thermochronology dating along three transectsperpendicular to the margin (Guinea, Ivory Coast and Benin) todetermine periods of maximum denudation.We compare these data to accumulation histories in passive marginbasins and discuss their stratigraphic expression according tothe type of margin segment they are preserved in.

International audience; The objective of the Transform Source to Sink Project (TS2P) is to link the dynamics of the erosion of theWest African Craton to the offshore sedimentary basins of the African margin of the Equatorial Atlantic atgeological time scales. This margin, alternating transform and oblique segments from Guinea to Nigeria, showsa strong structural variability in the margin width, continental geology and relief, drainage networks and subsidence/accumulation patterns. We analyzed this system combining onshore geology and geomorphology as well asoffshore sub-surface data.We produced paleogeographic maps at the scale of West Africa spanning the continental domain and offshorebasins since 200 Ma. Mapping spatial and temporal distribution of domains either in erosion (sources) or inaccumulation (sinks) document the impact of the successive rifting of Central and Equatorial Atlantic on thephysiography of the area. We use low temperature thermochronology dating along three transects perpendicular tothe margin (Guinea, Ivory Coast and Benin) to determine periods and domains of denudation in that framework.We compare these data to the Mesozoic accumulation histories in passive margin basins and discuss theirstratigraphic expression according to the type of margin segment they are preserved in. Syn-rift architectures(Early Cretaceous) are largely impacted by transform faults that define sub-basins with contrasted width of crustalnecking zone (narrower in transform segments than in oblique/normal segments). During the Late Cretaceouspost-rift, sedimentary wedges record a transgression along the all margin. Proximal parts of the sedimentarywedge are preserved in basins developing on segments with wide crustal necking zone while they were erodedaway in basins developing on narrow segments. As a difference, the Cenozoic wedge is everywhere preservedacross the whole width of the margin.

International audience; This paper reports an integrated, spatio-temporal analysis of the fracture-controlled paleo-fluid system in the Pico del Aguila anticline, a N-S trending fold located in the Sierras Exteriores, the southern front of the Spanish Pyrenees. Eight fracture sets (joints or faults) are recognized throughout the fold and are separated into a fracture sequence that is defined using field relationships and the remarkable temporal constraints offered by the syn-tectonic sedimentary deposits. This fracture sequence records a complex Paleocene to Early Oligocene structural evolution, including map-view, clockwise rotation and tilting of the fold axis. The geochemical analysis of calcite cements from the different mineralized fracture/vein sets reveals a compartmentalized fluid system during most of fold development. This initial paleofluid system was later perturbed when bending-related fractures associated with foreland flexure and outer arc extension triggered small-scale, vertical fluid migration. Fractures developed in shallow strata facilitated downward migration of surficial fluids that controlled the paleo-fluid system in the Late Priabonian/Stampian continental deposits. The study of the Pico del Aguila anticline depicts for the first time the evolution of a fluid system in a shallow, syn-depositional compressional setting, and results further strengthen the statement that fluids migrate vertically across stratigraphic boundaries take place during fold hinge-related deformation.

National audience; The clastic sedimentary record of passive margins is a function of lithosphericdeformation, eustasy and morphoclimatic evolution of sourcecontinental areas. The African passive/transform margin of the EquatorialAtlantic is a unique natural laboratory to explore the feedbacksbetween those processes during the Cenozoic. Indeed, onshore denudationand drainage history of the margin has been reconstructed by thespatial analysis of dated and regionally correlated geomorphic markersof former base levels. This onshore history can be compared to the offshoresedimentary record from the interpretation of seismic lines calibratedby biostratigraphy.We thus initiated a source to sink approach on the Ivory Coast - Ghanasegment of the margin between the Romanche and Chain fracture zones(from Ghana to Benin), which has been mainly fed by the Volta drainagesystem during the Cenozoic. Offshore data show that Cenozoicdeposits often lie over the Cretaceous on a major erosion surface. Paleogenedeposits are rarely preserved and affected by strong erosion,probably Oligocene in age. Neogene sedimentation is more continuouseven though Mid-Miocene slump deposits demonstrate important regionalslope destabilization processes. Plio-Pleistocene delta progradationsare well documented along the margin segment.The Oligocene erosion event correlates with a major regional drainagereorganization within the source domain ca. 30 Ma that resulted inthe inland growth of the Volta catchment. Since 30 Ma, the drainageconfiguration is stationary and allows for the detailed correlation of themorphoclimatic record (based on the sequence of lateritic paleolandsurfaces)with offshore stratigraphic architecture. Our approach will beextended to whole equatorial margin and will compare erosion and sedimentation budgets as well as the nature of exported regoliths and depositedclastics.

International audience; The Transform Source to Sink Project (TS2P) objective is to link theevolution of the sedimentary basins of the African margin of the EquatorialAtlantic and their source areas developing on West African Craton.The Equatorial Atlantic segment varies from a normal passive margin inthe North-West (Guinea), to an oblique margin (Sierra Leone and Liberia)and to a transform margin (Ivory Coast and Ghana). This evolutionis associated with variation in the margin width, continental relief, drainageorganization and subsidence/accumulation patterns that we analyzedusing seismic data and onshore geology.We compare syn-rift geometry and long-term stratigraphic history ofeach of these segments. Preliminary results in Sierra Leone and Liberiasegment show that syn-rift geometries (Lower Cretaceous) are increasinglyinfluenced by transform faults toward the South-East and theimmediate post-rift Upper Cretaceous wedge is associated with a marinetransgression and reactivation of transform faults. These results willthen be used to estimate sediment budgets and integrated in a sourceto-sink analysis where onshore denudation will be estimated by low-Temperature thermochronology

Competition between tectonic and climate is expressed throughout the sedimentation. Because of the retroactions existing between those two parameters, it is often hard to discriminate their relative influence. The Cenozoic is a period characterised both by a global cooling and the establishment of many orogenesis. The aim of this work was to understand how retractions between climate, tectonics and sedimentation can be documented in an ancient mountain range - the Pyrenees. Three main questions were discussed : (1) does the growth of the Pyrenees can significantly impact the climate, locally or more globally? (2) how does climate and tectonics influence the sedimentation ? (3) may a climatic shift influence the tectonic evolution of the Pyrenees and how? The first part was treated using stable isotope geochemistry (δ18O and δ13C) on carbonate marine (molluscs and dasycladales) and continental (charophytes gyrogonites) biomineralisations from the Paris basin and the South-Pyrenean foreland basin. Results show that the global climatic events of the Paleogene were recorded by the fossils analysed in those two basins, with the early Eocene climatic optimum, the Lutetian cooling, the middle Eocene climatic optimum and the Eocene - Oligocene glaciation. It implies that the growth of the Pyrenees should not have a significant influence on the climate during the Paleogene. However, a shift between the δ18O values of oysters in the Paris basin and in the Pyrenees during the middle Eocene supposes that the Pyrenean topography was soon high and could be estimated near 2000 meters. The second was addressed from a field study about the Lutetian carbonate deposits. It has highlighted that the carbonate platforms disappeared definitively at the Lutetian - Bartonian limit. This evolution seems to result from an environmental stress in response to an increase of the erosional flux. This event is not correlated to a particular tectonic event but is however synchronous with a climatic instability and the establishment of a significant glacioeustatism. Finally, we try to highlight a relationship between the climate and the tectonic in the Pyrenees. We have established a kinematic model, to better evaluate the sequence of shortening in the western area of the South-Pyrenean basin. Three main periods of shortening are identified between the middle Eocene and the Miocene. The comparison between the frontal accretionary flux and the outcoming flux coming from the axial zone, deduced from bibliographic data, reveals that a strong increase in erosion happened around the Eocene - Oligocene boundary. This event corresponds to the main climatic rupture of the Cenozoic, suggesting a climatic forcing on the erosion and the elevation of the Pyrenees., La compétition entre la tectonique et le climat s'exprime à travers la sédimentation. Or, du fait des fortes rétroactions existant entre ces paramètres, il est souvent difficile de discriminer leur influence relative. Ainsi, le Cénozoïque est une période présentant à la fois un refroidissement global et une phase orogénique majeure avec la collision alpine au sens large (depuis les Pyrénées à l'Ouest à la chaîne himalayenne à l'Est). Le but de cette thèse a été de comprendre comment s'expriment les rétroactions entre le climat, la tectonique et la sédimentation, dans une chaîne de montagne ancienne - les Pyrénées - dont les cadres sédimentologique, stratigraphique et tectonique, sont bien contraints. Trois questions principales ont été abordées : (1) est-ce que la croissance de cette seule chaîne de montagnes est susceptible d'influencer significativement le climat, localement ou à plus large échelle ? (2) de quelle manière le climat et la tectonique influencent la sédimentation ? (3) est-ce qu'un changement climatique est susceptible d'influencer l'évolution tectonique de cette chaîne de montagnes et de quelle manière ? La première partie a été abordée à travers à l'analyse géochimique de biominéralisations carbonatées provenant du bassin sud-pyrénéen (huîtres), comparée à celles de fossiles provenant du bassin de Paris (mollusques, dasycladales et characées), bassin intracratonique situé à proximité des Pyrénées. Les résultats montrent que les fossiles des deux bassins ont bien enregistré les événements climatiques globaux connus au Paléogène (Optimum climatique de l'Eocène inférieur, refroidissement du Lutétien, Optimum climatique de l'Eocène moyen et glaciation de la limite Eocène - Oligocène), signifiant que la croissance des Pyrénées n'a pas eu de conséquences directes sur le climat local. En revanche, ces résultats montrent que le δ18O des huîtres provenant des Pyrénées est plus négatif que celles du bassin de Paris. Le gradient latitudinal étant très réduit à cette période, ceci semble indiquer que le δ18O des huîtres pyrénéennes a été influencé par un apport d'eau ayant un δ18O négatif, signifiant une influence de la topographie pyrénéenne sur le δ18O des eaux de pluie et des rivières. La seconde partie a été abordée à partir d'une étude de terrain, caractérisant précisément les dépôts à l'Eocène moyen. Ceci a montré que les dernières plates-formes carbonatées ont définitivement disparues dans le bassin sud-pyrénéen à la limite Lutétien - Bartonien. Il semble qu'un stress environnemental dû à une intensification de l'érosion soit responsable de la disparition des producteurs carbonatés et ce, non pas uniquement à cause d'un forçage tectonique, mais également à cause de l'apparition d'un glacioeustatisme, c'est-à-dire d'un facteur climatique. Enfin, dans le but de mettre en évidence un éventuel forçage climatique sur le soulèvement des Pyrénées, nous avons établi un modèle cinématique reconstituant la séquence de déformation entre le Lutétien et le Miocène dans la partie ouest du bassin sud-pyrénéen. Trois phases de déformation successives ont été mises en évidence. La comparaison des flux entrant dans le prisme au cours du temps avec les flux d'érosion déduits de données de thermochronologie provenant de la bibliographie a révélé qu'il existait un important découplage entre les taux d'érosion et la quantité de matière entrant dans le prisme à la limite Eocène - Oligocène. Or, cette période est caractérisée par un changement climatique majeur dont l'impact sur les processus d'érosion a déjà été mis en évidence dans de nombreux travaux.

Genre Idiocythere Triebel, 1958 ESP��CE TYPE. ��� Idiocythere lutetiana Triebel, 1958., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on page 945, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["TRIEBEL E. 1958. - Zwei neue Ostracoden-Gattungen aus dem Lutet des Pariser Beckens. Senckenbergiana Lethaea 39: 105 - 117."]}

Leguminocythereis ? multicostata (Bosquet, 1852) (Fig. 6S) Cythere multicostata Bosquet, 1852: 59, pl. 2, fig. 12. Leguminocythereis multicostata ��� Apostolescu 1955: 252, pl. 3, fig. 39, 40. ���? Haskins 1970: tableau p. 14. ���? Keij 1957: 125, 126, pl. 13, figs 1, 2, pl. 18, fig. 9. ? Cytheretta multicostata ��� Ngatse 1985: 12. Leguminocythereis ? multicostata ��� Ducasse et al. 1985: 81, fig. 4. REMARQUES Leguminocythereis ? multicostata dont le lectotype, choisi par Keij (1957), provient du Lut��tien de Chaumont ou de la Ferme de l���Orme dans le Bassin de Paris est ��galement cit��e dans le Cuisien (Ngatse 1985) et dans l���Auversien (Apostolescu 1955; Keij 1957). Elle n���est pas connue en dehors du Bassin de Paris. Outre �� Grignon, nous l���avons observ��e dans le Lut��tien de la Ferme de l���Orme et dans celui de Villiers-Saint-Fr��d��ric. Nous avons observ�� deux types de valves et carapaces. Les unes s���identifient au lectotype figur�� par Keij. Les autres (deux valves et une carapace provenant de l�����chantillon GRS 11) pr��sentent les m��mes caract��res internes et une ornementation de m��me type mais distincte; elles ont un contour plus triangulaire avec extr��mit�� post��rieure r��guli��rement arrondie (Fig. 6T, U). Elles correspondent peut-��tre �� des m��les de la m��me esp��ce car les deux types de valves sont pr��sents dans le m��me ��chantillon. Plus vraisemblablement, compte tenu de l���importance des diff��rences, elles correspondent �� deux esp��ces distinctes. Leguminocythereis ? multicostata rappelle par ses contours et son ornementation �� Echinocythereis �� multicostata Deltel, 1963 (��oc��ne moyen de l���Aquitaine m��ridionale), esp��ce type de Ducassella Colin, 1999 (figuration in Ducasse et al. 1985). Elle s���en distingue notamment par sa marge ant��rieure moins aplatie et ses c��tes longitudinales mieux individualis��es. Int��rieurement, la dent cardinale post��rieure de L. ? multicostata Bosquet, 1852 est lob��e, alors que celle de Ducassella n���est pas d��crite., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on pages 937-938, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["BOSQUET J. 1852. - Description des Entomostraces fossiles des terrains tertiaires de la France et de la Belgique. Memoire de l'Academie Royale des Sciences de Belgique 24: 1 - 142.","HASKINS C. 1970. - Tertiary Ostracoda from the isle of Wight and Barton, Hampshire, England: part V. Revue de Micropaleontologie 1: 13 - 29.","KEIJ A. 1957. - Eocene and Oligocene Ostracoda of Belgium. Institut royal des sciences naturelles de Belgique 136: 1 - 210.","NGATSE R. 1985. - Ostracodes du Cuisien du Bassin de Paris. Memoire de DEA de l'Universite de Paris, inedit, 46 p.","DUCASSE O., GUERNET C. & TAMBAREAU Y. 1985. - Paleogene, in OERTLI H. (ed.), Atlas des Ostracodes de France. Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire 9: 259 - 311.","DELTEL B. 1963. - Nouveaux Ostracodes de l'Eocene et de l'Oligocene de l'Aquitaine meridionale. Actes de la Societe linneenne de Bordeaux 100: 127 - 221."]}

Triginglymus angulatopora (Reuss, 1850) (Fig. 6H, I, K) Cypridina angulatopora Reuss, 1850: 86, pl. 10, fig. 32. non Cythere angulatopora ��� Bosquet 1852: 67, pl. 3, fig. 4. Cythere jonesiana Bosquet, 1852: 67, pl. 3, fig. 4. Cythere angulatopora ��� Jones & Sherborn 1889: 22, pl. 3, fig. 15. Leguminocythereis jonesiana ��� Apostolescu 1955: 252, pl. 3, figs 37, 38. Triginglymus angulatopora ��� Keij 1957: 127, pl. 18, fig. 10, pl. 19, fig.7; 1958: 65. ��� Ducasse et al. 1985: pl. 82, figs 6, 7, tableau 14. ��� Gramann 1986: 416. ? Leguminocythereis angulatopora ��� Deltel 1961: 175, 176, pl. 17, fig. 285. Leguminocythereis angulatopora ��� Pietrzeniuk 1969: 77. ��� Blondeau M.-A. 1971: 45, 46, pl. 5, fig. 1. ��� Margerel et al. 1976: 22. REMARQUES Triginglymus angulatopora est commune dans le Lut��tien des bassins de Paris, de Bruxelles et de la basse Loire (Apostolescu 1955; Keij 1957; Blondeau M.-A. 1971; Margerel et al. 1976). Elle est cit��e dans l���Auversien du Bassin de Paris, le Bartonien de Belgique et des Pays-Bas (Keij 1957, 1958), l�����oc��ne 5 du nord-est de l���Allemagne (Pietrzeniuk 1969; Gramann 1986), l�����oc��ne et, plus douteux, l���Oligoc��ne sud-aquitain (Deltel 1961)., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on pages 938-940, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["BOSQUET J. 1852. - Description des Entomostraces fossiles des terrains tertiaires de la France et de la Belgique. Memoire de l'Academie Royale des Sciences de Belgique 24: 1 - 142.","JONES T. & SHERBORN C. 1889. - A Supplementary Monograph of the Tertiary Entomostraca of England. Palaeontographical Society, London, 55 p.","KEIJ A. 1957. - Eocene and Oligocene Ostracoda of Belgium. Institut royal des sciences naturelles de Belgique 136: 1 - 210.","DUCASSE O., GUERNET C. & TAMBAREAU Y. 1985. - Paleogene, in OERTLI H. (ed.), Atlas des Ostracodes de France. Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire 9: 259 - 311.","DELTEL B. 1961. - Les Ostracodes du Paleogene moyen et superieur d'Aquitaine meridionale. These de la Faculte des Sciences de l'Universite de Bordeaux, 217 p.","PIETRZENIUK E. 1969. - Taxonomische und biostratigraphische Untersuchungen an Ostracoden des Eozan 5 im Norden der Deutschen Demokratischen Republik. Palaontologischen Abdhandlungen 4: 1 - 162.","MARGEREL J. - P., BLONDEAU M. - A. & OLLIVIER P. 1976. - Contribution a l'etude micropaleontologique de l'Eocene du Bassin de Campbon (Loire-Atlantique). Bulletin de la Societe Geologique et Mineralogique de Bretagne 8: 1 - 64.","ROEMER F. 1838. - Die Cytherinen des Mollasse-Gebirges. Neues Jahrbuch fur Mineralogie und Palaontologie 6: 514 - 519.","KEIJ A. 1958. - Note on the Lutetian Ostracoda of Damery (Marne), France. Koninklingen Nederland Akademie van Wetenschappen 61 (1): 63 - 73."]}

Genre Pokornyella Oertli, 1956 ESP��CE TYPE. ��� Cythere limbata Bosquet, 1852. REMARQUES Le genre Porkonyella, thermophile, est pr��sent de l�����oc��ne inf��rieur �� l���Oligoc��ne dans le Bassin de Paris et d���Aquitaine (Ducasse et al. 1985). Il s�����teint en M��diterran��e au Pl��istoc��ne inf��rieur (Guernet 2005)., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on page 941, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["OERTLI H. 1956. - Ostrakoden aus der oligozanen und miozanen Molasse der Schweiz. Schweizerischen Palaontologischen Abdhandlungen 74: 1 - 119.","BOSQUET J. 1852. - Description des Entomostraces fossiles des terrains tertiaires de la France et de la Belgique. Memoire de l'Academie Royale des Sciences de Belgique 24: 1 - 142.","DUCASSE O., GUERNET C. & TAMBAREAU Y. 1985. - Paleogene, in OERTLI H. (ed.), Atlas des Ostracodes de France. Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire 9: 259 - 311.","GUERNET C. 2005. - Ostracodes et stratigraphie du Neogene et du Quaternaire mediterraneen. Revue de Micropaleontologie 48: 83 - 121."]}

Paracytheridea grignonensis Keij, 1957 (Fig. 8N) Paracytheridea grignonensis Keij, 1957: 160,161, pl. 19, fig. 11, pl. 22, fig. 1. ��� Deltel 1961: 126, 127, pl. 9, fig. 137. ��� Haskins 1970: 18, pl. 2, figs 1-3. ��� Blondeau M.-A. 1971: 91, pl. 9, fig. 20. ��� Ducasse et al. 1985: pl. 87, fig. 11, tableau 14. ���? Monostori 1998: 62, pl. 16, fig. 9. ��� Lord et al. 2009: pl. 5, fig. 4, tableau p. 382. Paracytheridea tuberosa ��� Apostolescu 1955: 250, pl. 2, figs 26-27. Non Lienenklaus, 1900. REMARQUES Paracytheridea grignonensis dont le type provient de Grignon est connue dans le Lut��tien du Bassin de Paris (Apostolescu 1955; Keij 1957), de la basse vall��e de la Loire (Blondeau M.-A. 1971) et du bassin du Hampshire (Haskins 1970; Lord et al. 2009). Elle est cit��e dans l�����oc��ne moyen et sup��rieur aquitain (Blondeau, 1971) ainsi que dans l�����oc��ne moyen et l���Oligoc��ne sud-aquitain (Deltel 1961; Ducasse et al. 1985), ce qui est plus surprenant. Enfin, elle serait pr��sente dans l�����oc��ne sup��rieur de Hongrie (Monostori 1998)., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on page 950, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["KEIJ A. 1957. - Eocene and Oligocene Ostracoda of Belgium. Institut royal des sciences naturelles de Belgique 136: 1 - 210.","DELTEL B. 1961. - Les Ostracodes du Paleogene moyen et superieur d'Aquitaine meridionale. These de la Faculte des Sciences de l'Universite de Bordeaux, 217 p.","HASKINS C. 1970. - Tertiary Ostracoda from the isle of Wight and Barton, Hampshire, England: part V. Revue de Micropaleontologie 1: 13 - 29.","DUCASSE O., GUERNET C. & TAMBAREAU Y. 1985. - Paleogene, in OERTLI H. (ed.), Atlas des Ostracodes de France. Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire 9: 259 - 311.","MONOSTORI M. 1998. - Eocene Ostracods of Hungary. Systematical part 1 (Cytheracea 1). Annales de l'Universite des Sciences de Budapest, section Geologie 31: 123 - 144.","LORD A., WHITTAKER J. & KING C. 2009. - Paleogene, in WHITTAKER J. & HART M. (eds), Ostracods in British Stratigraphy. Special publication of the Micropaleontological Society: 373 - 409.","BLONDEAU M. - A. 1971. - Contribution a l'etude des Ostracodes eocenes des bassins de Campbon et de Saffre (Loire-Atlantique). These de l'Universite de Nantes, 157 p."]}

Genre Cytheretta M��ller, 1894 ESP��CE TYPE. ��� Cytheretta rubra M��ller, 1894., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on page 946, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["MULLER G. W. 1894. - Die Ostracoden des Golfes von Neapel. Fauna und Flora des Golfes von Neapel 21: 1 - 403."]}

Phalcocythere horrescens (Bosquet, 1852) (Fig. 5U) Cythere horrescens Bosquet, 1852: 119, pl. 6, fig. 5. Trachyleberis horrescens ��� Apostolescu 1955: 272, pl. 8, figs 125-126. ��� Blondeau M.-A. 1971: 54, 55, pl. 6, figs 1-5. Hirsutocythere horrescens ��� Keij 1957: 101, 102, pl. 15, fig. 4, pl. 17, figs 6, 7. ���? Deltel 1961: 169, 170, pl. 16, fig. 281. Trachyleberis ? horrescens ��� Pietrzeniuk 1969: 50. Phalcocythere horrescens Siddiqui, 1971: 57, 58, pl. 29, fig.5, pl. 30, figs 1-6, pl. 33, figs 12-13. ��� Ducasse et al. 1985: pl. 78, figs 15, 17, tableau 14. ��� Monostori 1998: 46, 47, pl. 16, fig. 8, pl. 17, fig. 1. ��� non Phalcocythere horrescens Guernet in Merle 2008a: pl. 4, fig. 2. REMARQUES Le lectotype de Phalcocythere horrescens provient de Grignon (Keij 1957; Siddiqui 1971).L���esp��ce est cit��e au Lut��tien en Belgique (Keij 1957) et de l���Ypr��sien �� l���Auversien dans le Bassin de Paris (Apostolescu 1955; Keij 1957; Siddiqui 1971; Ducasse et al. 1985). Elle est ��galement pr��sente dans le Lut��tien de Loire- Atlantique (Blondeau M.-A. 1971), dans l�����oc��ne 5 de l���Allemagne orientale (Pietrezeniuk 1969) et dans l�����oc��ne moyen de Hongrie (Monostori 1998). Elle est cit��e dans l�����oc��ne (Ducasse et al. 1985; Deltel 1961) et m��me dans l���Oligoc��ne aquitain, mais seule une carapace lut��tienne est figur��e (Deltel 1961)., Published as part of Guernet, Claude, Huyghe, Damien, Lartaud, Franck, Merle, Didier, Emmanuel, Laurent, G��ly, Jean-Pierre, Michel, Florent & Pilet, Oph��lie, 2012, Les Ostracodes de la faluni��re de Grignon (Lut��tien du Bassin de Paris): implications stratigraphiques, pp. 909-959 in Geodiversitas 34 (4) on page 935, DOI: 10.5252/g2012n4a12, http://zenodo.org/record/4597495, {"references":["BOSQUET J. 1852. - Description des Entomostraces fossiles des terrains tertiaires de la France et de la Belgique. Memoire de l'Academie Royale des Sciences de Belgique 24: 1 - 142.","KEIJ A. 1957. - Eocene and Oligocene Ostracoda of Belgium. Institut royal des sciences naturelles de Belgique 136: 1 - 210.","DELTEL B. 1961. - Les Ostracodes du Paleogene moyen et superieur d'Aquitaine meridionale. These de la Faculte des Sciences de l'Universite de Bordeaux, 217 p.","PIETRZENIUK E. 1969. - Taxonomische und biostratigraphische Untersuchungen an Ostracoden des Eozan 5 im Norden der Deutschen Demokratischen Republik. Palaontologischen Abdhandlungen 4: 1 - 162.","DUCASSE O., GUERNET C. & TAMBAREAU Y. 1985. - Paleogene, in OERTLI H. (ed.), Atlas des Ostracodes de France. Bulletin des Centres de Recherches Exploration-Production Elf-Aquitaine, Memoire 9: 259 - 311.","MONOSTORI M. 1998. - Eocene Ostracods of Hungary. Systematical part 1 (Cytheracea 1). Annales de l'Universite des Sciences de Budapest, section Geologie 31: 123 - 144.","MERLE D. 2008 a. - Une selection de planches de fossiles caracteristiques, in MERLE D. (ed.), Stratotype lutetien. Biotope, Meze; Museum national d'Histoire naturelle, Paris; BRGM, Orleans. Collection Patrimoine geologique: 138 - 171."]}