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International audience; Aeshna caseneuvensis sp. nov., the second oldest representative of the genus Aeshna, is described and figured from the lowermost Oligocene of Luberon in southeastern France. The oldest described species in this genus is from the uppermost Eocene of Colorado in USA. Their occurrence in very distant areas in an interval of time of less of five millions years strongly suggests that the genus is older, possibly appearing during the middle Eocene, as it is still unknown in the early Eocene odonate faunas. The specimen could be studied thanks to a technique of photograph under UV light newly developed by one of us (RG).

International audience

National audience; La transition de l'Éocène Greenhouse vers l'Oligocène Icehouse (∼40 à 32 Ma)résulte de l'interaction entre une baisse du CO2, des changements paléogéographiqueset le forçage orbital. Cependant, son expression en termes de biomes et de climats surles continents est très hétérogène : certaines régions semblent n'enregistrer aucunchangement (Patagonie, Afrique), alors que d'autres sont profondément impactées(Asie, Amérique du Nord) (Pound et Salzmann, 2017, Hutchinson et al., 2020). Enoutre, la Grande Coupure, un événement majeur de dispersion faunistique de l'Asievers l'Europe et l'Amérique du Nord se produit tardivement (∼ 34 Ma), bien après lamise en place des ponts terrestres reliant ces continents (dès ∼38 Ma) (Akhmetiev etZaporozhets, 2014). Cela suppose que d'importantes contraintes climatiques ontempêché ces migrations d'avoir lieu plus tôt. De plus, lorsque la résolutionstratigraphique le permet, le forçage orbital est clairement enregistré dans différentesrégions du globe, et pourrait avoir induit une importante variabilité climatique à cetteépoque, comme le suggèrent différentes études de modélisation (Licht et al., 2014,Zhang et al., 2012, Keery et al., 2018).A l’aide du modèle de système terre IPSL-CM5A2 et de végétation dynamiqueORCHIDEE, nous testons des configurations orbitales extrêmes sur unepaléogéographie tardi-Eocène, afin d'évaluer leur impact sur le climat et la végétationde cette période. Nos résultats montrent deux aspects majeurs : (1) les régionssubtropicales du sud-est asiatique pourraient avoir connu périodiquement un régimede mousson, en alternance avec des périodes plus sèches ; (2) les ponts continentauxétroits tels que les détroits de Béring et de Turgai présentent d'importants changementsde végétation en fonction de l'obliquité, allant de la forêt tempérée à des zonesarbustives ouvertes. Nous proposons que le forçage orbital a pu induire des barrièresclimatiques et/ou biologiques périodiques contre la dispersion de la faune, et pourraitdonc avoir contraint la Grande Coupure américaine et européenne.

International audience; Ronzotherium is one of the earliest Rhinocerotidae in Europe, which first appeared just afterthe Eocene/Oligocene transition (Grande Coupure), and became extinct at the end of the Oligocene. It is a large-sized rhinocerotid, with a special position in the phylogeny of this group, as being one of the earliest-branching true Rhinocerotidae. However, its intra-generic systematics has never been tested through computational phylogenetic methods and it is basically unknown. Its taxonomical history has gone through numerous complications, and thus we aim to provide here a complete revision of this genus, through phylogenetic methods. After a re-examination of all type specimens (five supposed species) as well as of most well-preserved specimens from all over Europe and ranging through the complete Oligocene epoch, we performed a parsimony analysis to test the position of some problematic specimens. According to our results, five species can be distinguished, Ronzotherium velaunum (type species), R. filholi, R. elongatum and R. romani as well as a new species: R. heissigi sp. nov. We also drastically re-interpret its anatomy and show that the ‘short-limbed’ “Diaceratherium” massiliae, described from Southern France, can be considered as a junior synonym of R. romani. Finally, we exclude the Asian species “Ronzotherium” orientale and “Ronzotherium” brevirostre from Ronzotherium and we consider R. kochi as a junior synonym of R. filholi.

ISSN électronique : 2492-2447; International audience; The Early Oligocene limestone formation called Calcaires de Campagne-Calavon in the Luberon region increases noticeably the world fossil record of birds, for several reasons. First, the fossil birds "on plate" found in this formation are particularly well preserved and complete or near-complete for most of them. Moreover, the fossil birds from the Parc du Luberon are particularly interesting for the systematic diversity they represent: a minimum of 26 different species for less than 30 well-identified specimens, corresponding to at least 18 different families, which is a high representativeness. In addition, these specimens are often the earliest known representatives of their respective families worldwide (or more inclusive taxa). These fossils are therefore of prime importance, notably for the estimation of divergence ages of certain bird taxa (molecular clock calibration), and more generally to better apprehend the evolution of morphology and of geographical distribution of birds since the Oligocene. These fossils also yield clues about paleoenvironments 30 million years ago in the region. All these aspects of research are reviewed here, based on published works as well as on original data, incorporating six new fossils.; Les Calcaires de Campagne-Calavon, formation de l'Oligocène inférieur du Luberon, enrichissent indéniablement le registre fossile mondial des oiseaux, et ce pour plusieurs raisons. Tout d'abord, les oiseaux fossiles « en plaques » s'y trouvant sont tout particulièrement bien conservés et complets ou quasi complets pour la grande majorité. En plus de leur préservation exceptionnelle, les fossiles du Parc du Luberon sont tout particulièrement intéressants par la diversité qu'ils mettent en avant : un minimum de 26 espèces différentes pour moins de 30 spécimens assez bien identifiés, représentant au moins 18 familles différentes, ce qui est une représentativité très forte. De plus, ces spécimens sont souvent les plus anciens représentants connus de leurs familles respectives (ou parfois de taxons plus inclusifs). Ces fossiles sont donc d'importance primordiale, notamment pour l'estimation de l'âge de divergence de certains taxons d'oiseaux (calibration des horloges moléculaires), et plus largement pour mieux appréhender l'évolution de la morphologie et de la distribution géographique des oiseaux depuis l'Oligocène, tout en apportant des précisions sur le type de paléoenvironnement qui régnait dans cette région il y a 30 millions d'années (Ma). Ces différents aspects sont passés en revue ici, à partir des différentes publications, et aussi de données inédites, comportant six nouveaux fossiles.

The paleogene molasses (Eocen, Oligocen) which fill the Castrais and Albigeois basins (eastern Aquitaine, France) contain several conglomerate spreads with elements of Paleo-Pyrenean origin, which have been assimilated by the authors to the “Poudingues de Palassou” of the northern edge of the central Pyrenees. These levels, better named in the Tarn under the name « Poudingues de type Puylaurens », range from the Upper Eocene (Bartonian, Priabonian) to the Rupelian. If the syntectonic origin of the Eocene-age conglomerates is proven, the climatic origin of the Rupelian-age conglomerates is more likely. These conglomerates also bear witness to the existence since the Bartonian of a paleorelief prefiguring the Montagne Noire., Les molasses paléogènes (Eocène, Oligocène) qui comblent les bassins du Castrais et de l'Albigeois (Aquitaine orientale) renferment plusieurs épandages conglomératiques à éléments d'origine paléo-pyrénéenne qui ont été assimilés par les auteurs aux « Poudingues de Palassou » de la bordure nord des Pyrénées centrales. Ces niveaux, mieux nommés dans le Tarn sous le terme de « Poudingues de type Puylaurens », s'y échelonnent de l'Eocène supérieur (Bartonien, Priabonien) au Rupélien. Si l'origine syntectonique des conglomérats d'âge éocène est avérée, l'origine climatique des conglomérats d'âge rupélien est plus vraisemblable. Ces conglomérats paléogènes témoignent aussi de l'existence depuis le Bartonien, d'un paléorelief préfigurant la Montagne Noire.

International audience; The presence of “geological” amber (or “succin” in old French monographs) has been reported for several centuries in the Mesozoic deposits of Provence, southeastern France. Diverse amber-bearing sites were inventoried by the authors but their location and stratigraphical context remain unclear for most of them. In the past decades, various data concerning chemistry, palaeontological content and comparison with archaeological discoveries improved our knowledge of the ambers of Provence, but only those of Cretaceous age. The present paper aims at providing a comprehensive description of all the presently known amber-bearing deposits of Provence, including the description of new sites. We highlight the great potential of Provence ambers and allow to consider a wider time range, from the Early Cretaceous to the Miocene.; La présence d’ambre « géologique » ou « succin » a été signalée en Provence depuis plusieurs siècles. Un certain nombre de gisements ambrifères crétacés, plus ou moins bien localisés précisément, avaient été ainsi répertoriés. Plus récemment des données variées concernant la chimie, le contenu paléontologique, la comparaison avec des ambres archéologiques ont amené à mieux connaître les ambres, uniquement d’âge crétacé, de la région. La présente revue des gisements ambrifères de Provence, incluant la découverte de nouveaux sites ambrifères, permet de mettre en évidence le potentiel en ambre de la Provence et d’envisager un large éventail de temps jusqu’à présent inenvisagé allant du Crétacé inférieur au Miocène.

Reduction of the anterior dentition (i.e. incisors and canines) is a major adaptative trait of the Rhinocerotidae among Perissodactyla. However, the corresponding evolutionary sequence was lacking a robust phylogenetic frame to support it thus far. Here, we describe a new Oligocene species of Rhinocerotinae,Mesaceratheriumsp. nov. from the Swiss locality of Bumbach (MP25 reference level). In addition, we identify the only known complete mandible ofEpiaceratherium magnum, an early-branching rhinocerotid, as well as one of the earliest European rhinoceroses. We also compute a parsimony analysis based on morpho-anatomical characters to assess their phylogenetic position and elucidate the early evolution of the Rhinocerotidae. Our results allow to propose a new scenario for the reduction of the anterior dentition in which upper and lower dentitions would have undergone distinct evolutionary trajectories.

International audience; Two sedimentary basins are identified in the Turkana Depression (East African Rift System, Kenya). One of them, the Ekitale Basin, is presented in detail. Located on the western rift shoulder of the northern Turkana Depression, the preserved portion of the Ekitale Basin is 3–5‐km wide and bordered by N40°–50° normal faults. These normal faults were inherited from the reactivation of pre‐existing basement structures. The Ekitale Basin is filled by the ~75‐m‐thick Topernawi Formation. The lower portion of the formation provides evidence that the basin was occupied by a lake, bordered by alluvial fans, and into which river‐derived turbiditic complexes were deposited. The upper portion is comprised of pyroclastic deposits, originating from volcanic activity, and interbedded with fluvial deposits emplaced during periods of volcanic quiescence. The Ekitale Basin opened just after 28 Ma and was abandoned prior to 25 Ma, placing it after the deposition of the Oligocene Traps (ca. 33.9–27 Ma) and prior to the rift climax (after 14 Ma). This syn‐rift basin largely impacts our understanding of the Cenozoic rift evolution in the Turkana Depression. It helps to identify, for the first time, the first pulse of extension of the Cenozoic rifting, revealing a two‐step rifting scenario for the northern Turkana Depression. The Ekitale Basin, and analogous syn‐rift basins, is believed to have developed from the reactivation of pre‐existing structures during a period of extension marked by low differential stress and a low amount of extension.

International audience; Paleogene deposits of Peruvian Amazonia have yielded the oldest caviomorph rodent communities from South America, and the clues that their early diversification had occurred in this area. Here we report fossil dental remains of rodents from two new sections located in the vicinity of Juanjui and Balsayacu (San Martín Department, Peruvian Amazonia). Analyses of the occlusal morphology of cheek teeth and of the incisor enamel microstructure indicate the occurrence of basal caviomorphs (such as CachiyacuyAntoine, Marivaux, Croft, Billet, Ganerød, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi, 2012, CanaanimysAntoine, Marivaux, Croft, Billet, Ganerød, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi, 2012, and EoespinaFrailey & Campbell, 2004, genera so far known from late middle Eocene deposits of Contamana, Pe-ruvian Amazonia) in levels situated in the lower part of the studied stratigraphic section. More derived taxa (such as Eoincamys Frailey & Campbell, 2004), known from early Oligocene deposits of Tarapoto/Shapaja and Santa Rosa, Peruvian Amazonia) occur only in upper levels of the section. Based on these considerations, the rodent-bearing localities of the Juanjui/Balsayacu area seem to be intermediate in age between the Contamana Eocene localities and the Tarapoto/Shapaja Oligocene ones and the Santa Rosa ?Eocene/Oligocene one. These new data document a poorly known period in Western Amazonia, in providing a sedimentological record most likely documenting the late middle Eocene, the late Eo-cene and the earliest Oligocene interval. Furthermore, the existence of a long temporal hiatus between Canaanimys-Cachiyacuy-Potamotrygon ucayalensis assemblages (Contamana, Pozo Formation; Balsayacu; lower levels at Juanjui) and Eoincamys-yielding faunas (Santa Rosa; Tarapoto/Shapaja; uppermost levels at Juanjui) is demonstrated in a single continuous and long-ranging stratigraphic section at Juanjui.; Le Paléogène d’Amazonie péruvienne a livré les plus anciennes communautés de rongeurs caviomorphes d’Amérique du Sud, lesquelles sont le résultat des premières phases de diversification de ce groupe. Ce travail présente l’étude de restes dentaires inédits de rongeurs fossiles issus de deux nouvelles sections situées à proximité des villes de Juanjui et de Balsayacu (Département de San Martín, Amazonie péruvienne). Les analyses de la morphologie occlusale des dents jugales et de la microstructure de l’émail des incisives indiquent la présence de taxons basaux tels que les genres Cachiyacuy Antoine, Marivaux, Croft, Billet, Ganerød, Jaramillo, Martin, Orliac, Tejada, Altamirano, Duranthon, Fanjat, Rousse & Salas Gismondi, 2012, Canaanimys Antoine, Marivaux, Croft, Billet, Ganerød, Jaramillo, Martin, Orliac, Tejada, Altami-rano, Duranthon, Fanjat, Rousse & Salas Gismondi, 2012, et Eoespina Frailey & Campbell, 2004, dans les niveaux inférieurs de la série sédimentaire, auxquels succèdent des taxons plus dérivés, comme Eoinca-mys Frailey & Campbell, 2004, dans des niveaux plus récents. Ces taxons témoignent d’une morphologie intermédiaire entre ceux documentés en Amazonie péruvienne dans les localités éocènes de Contamana (fin de l’Éocène moyen) et ceux des localités oligocènes de Tarapoto/Shapaja et Santa Rosa (?Éocène supérieur/Oligocène inférieur). Ces fossiles apportent ainsi une documentation inédite en Amazonie, en ce que les secteurs de Juanjui et de Balsayacu présentent des dépôts sédimentaires couvrant vraisembla-blement la fin de l’Éocène moyen, une partie de l’Éocène supérieur et la base de l’Oligocène. Enfin, la continuité stratigraphique de la longue section de Juanjui permet de démontrer l’existence d’un hiatus temporel significatif entre les assemblages à Canaanimys-Cachiyacuy-Potamotrygon ucayalensis (Contamana, Formation Pozo ; base de la section de Juanjui ; Balsayacu) et ceux à Eoincamys (Santa Rosa ; Tarapoto/Shapaja ; sommet de la section de Juanjui).

International audience; Eight samples from Oligocene sedimentary rocks of the Marseille-Aubagne basins have been analysed for their detrital zircon age spectra. These age spectra provide information about the regional evolution, from Oligocene to Archaean times. The Carboniferous Variscan and the Late Cretaceous to Eocene Pyreneo-Provencal belts represent the latest main tectonic, magmatic, and volcanic events that formed the major zircon age populations found in studied sediments. The obtained detrital zircon age record of the Marseille-Aubagne basins comprises eleven detrital zircon age clusters. They reflect the long and complex geologic history of the sediments source areas and can be ascribed to the opening of the western Mediterranean, the Variscan, Cadomian and Pan-African belts, to an unknown Mesoproterozoic event, to the Eburnean orogeny of West Africa and to the different tectono-metamorphic events that took place in Archaean times. In general, the Palaeo- and Mesozoic events are ascribed to the dispersal of Western and Eastern Gondwana and the Pangaean supercontinent cycle. Thus, the successive recycling of zircon grains from older and the incorporation of them to younger belts lead to new geodynamical models for the northern Gondwana margin evolution. Significant amounts of Mesoproterozoic detrital zircon are at odds with previous hypotheses and re-open the question of the provenance of these zircon age populations. Therefore, this tiny tertiary basin is a natural archive which records the main geological events in SE France and its vicinity.

International audience; Fossil insects are very rarely found in sediments of deep marine origin. Nevertheless they can be of great interest to trace past events such as trans-oceanic migrations. Here we document the first fossil insects from Iran, viz. several alate ants dead during mating swarms and a migratory locust, found in the pelagic Oligocene sediments of the Zagros Mountains. This locust represents the first putative indication of insect migrations between the Arabian-African and Asiatic continents through the Parathetys, probably in relation with the development of open grassland biotas in these areas.

International audience; New specimens of rhinocerotids including a complete skull of Diaceratherium asphaltense and a series of associated dental and postcranial elements of D.aginense and Pleuroceros pleuroceros have been discovered in two localities of the Swiss Molasse Basin: Bühler (?latest Oligocene-earliest Miocene, Canton Appenzell-Ausserhoden) and Sous le Mont (Early Miocene, Canton Bern). The record of D.asphaltense in Bühler may push its First Appearance Datum back to the latest Oligocene.Pleuroceros pleuroceros and Diaceratherium aginense co-occur at Sous le Mont. This assemblage is typical of the Agenian age in Western Europe. Sous le Mont is the second Swiss occurrence of P.pleuroceros beside Wischberg (MN1).

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

International audience; The Pir-Sabz Section of the Asmari Formation is located in the Interior Fars province, Zagros Basin (Iran). The Asmari Formation at the study area is 312 m in thickness and formed by massive bedded limestone. According to the identified index microfossils, three Oligocene assemblage biozones were recorded: 1) Globigerina spp., 2) Lepidocyclina – Operculina – Ditrupa, and 3) Archaias asmaricus – Archaias hensoni. Twelve facies types were recognized according to their texture, occurrence and abundance of foraminifera, scleractinian corals and other skeletal grains: F1 Bioclastic planktonic foraminiferal wackestone–packstone, F2 Bioclastic planktonic foraminiferal echinoid packstone, F3 Bioclastic Operculina packstone, F4 Bioclastic Lepidocyclinidae packstone–rudstone, F5 Bioclastic coralline algal Lepidocyclinidae packstone–rudstone, F6 Bioclastic Lepidocyclinidae – Nummulitidae wackestone–packstone–grainstone, F7 Bioclastic Lepidocyclinidae – Neorotalia – coral packstone–rudstone, F8 Coral boundstone, F9 Bioclastic porcellaneous foraminifera – coral packstone, F10 Bioclastic coralline algal bryozoan wackestone–packstone, F11 Bioclastic benthic foraminifera (perforate and imperforate) wackestone–packstone, and F12 Bioclastic benthic foraminifera (imperforate) wackestone–packstone. From the base to the top of the section the facies types indicate: F1 aphotic zone and outer shelf; F2 aphotic to oligophotic zones on the outer and middle shelf (distal); F3 and F4 oligophotic zone and distal middle shelf; F5, F6 and F7 mesophotic zone situated on the middle shelf (proximal); F8, F9, F10 and F11 euphotic zone and inner shelf (open marine), F12 euphotic zone and inner shelf (slightly restricted). The Pir-Sabz coral fauna has a clear Mediterranean affinity and is represented by at least six different scleractinian species which formed a non-reefal coral community on the proximal middle-shelf.

The establishment of the 3rd edition of the geological map Aubagne-Marseille at 1/50.000 scale, gave us the opportunity to study and map the Oligocene continental series which constitutes the sedimentary filling of the Marseille-Aubagne basin and other smaller neighboring Oligocene basins. Mapping was made at the 1/12.500 scale while detailed lithological sections were logged and sampled for biostratigraphical and sedimentological (microfacies) investigations. A compilation of previous geological field-works and drillings carried out on the Marseille-Aubagne basin since the fundamental work of Depéret (1889) allowed us to provide complementary data on the Oligocene stratigraphy. Our survey led us to establish a stratigraphical subdivision of the Oligocene series different from that proposed by Nury et al. in the 3rd edition of the map and notice Aubagne-Marseille (2018) and closer to the former stratigraphical scheme of Deperet (1889). In particular, thanks to accurate correlations, we develop here the idea that there is only one stratigraphical series with lateral facies variations on the whole of a single Oligocene basin, contrary to the idea supported by Nury et al. of the existence of three stratigraphical series in three independent sub-basins. In conclusion, we present the consequences that our results have on the geodynamical interpretation of the Oligocene basin Marseille-Aubagne.

We investigate the enamel microstructure of 37 isolated rodent incisors from several late middle Eocene and late Oligocene localities of Contamana (Loreto Department, Peruvian Amazonia), and from the early Oligocene TAR-01 locality (Shapaja, San Martín Department, Peruvian Amazonia). All incisors show an enamel internal portion with multiserial Hunter-Schreger Bands (HSB). The late middle Eocene localities of Contamana yield incisors with subtypes 1, 1–2, and 2 of multiserial HSB; TAR-01 yielded incisors with subtypes 1–2, 2, 2–3, and 3 of multiserial HSB; and the late Oligocene localities of Contamana, incisors with subtypes 1–2, 2, and 2–3 of multiserial HSB. Based on our current knowledge of the South American and African rodent fossil records and given the primitiveness of the Eocene caviomorph faunas, it may be expected that the hystricognath pioneer(s) who have colonized South America from Africa sometime during the middle Eocene, most probably had incisors that displayed a multiserial enamel with an interprismatic matrix arrangement characterizing the subtype 1 (or subtype 1 + the subtype 2 and/or the transitional 1–2) of multiserial HSB. In contrast, the derived subtypes 2–3 and 3 conditions were subsequently achieved but likely rapidly, as evidenced by its record as early as the late Eocene/early Oligocene (e.g., Santa Rosa, Shapaja, and La Cantera), and seemingly evolved iteratively but only in the Octodontoidea clade. Fil: Boivin, Myriam. Institut Des Sciences de L'evolution de Montpellier; Francia. Centre National de la Recherche Scientifique; Francia. Université de Montpellier; Francia Fil: Marivaux, Laurent. Institut Des Sciences de L'evolution de Montpellier; Francia. Université de Montpellier; Francia. Centre National de la Recherche Scientifique; Francia Fil: Salas Gismondi, Rodolfo. Universidad Nacional Mayor de San Marcos; Perú Fil: Vieytes, Emma Carolina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Zoología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Antoine, Pierre Olivier. Institut Des Sciences de L'evolution de Montpellier; Francia. Université de Montpellier; Francia

International audience; Since its first erection almost 200 years ago, palaeontologists have assigned to the genus Anthracotherium many species, some with dubious descriptions. Although it is a key taxon for specifying the invasion of Europe by terrestrial mammals during the well-studied Grande Coupure Event at the beginning of the Oligocene, the genus has never been reviewed before. A recent interest in the relationships of anthracotheres and hippopotamids highlighted its importance for the understanding of diversity of anthracotheres. Herein, we conduct a systematic review of most European anthracotheriine species, including some Asian and American species in order to establish a more exhaustive anthracotheriine phylogeny. A cladistic analysis focusing on anthracotheriines supports us in redefining and clarifying the systematic status of most genera and species of this subfamily. Furthermore, our study results in the division of Anthracotherium into two different genera, the definition of a new taxon, Paenanthracotherium gen. nov., and the creation of a new species from previously described material, Paenanthracotherium bergeri sp. nov. Additionally, our phylogeny suggests a new palaeogeographical scenario implying several dispersal events from Asia to Europe before and during the Grande Coupure Event. This study marks the first step to a much-needed global review of anthracotheriines, including the American and Asian specimens.

Since the emergence of the carbonated platform of the southeastern basin of France during the Albian-Cénomanian, a long process of complex polyphased karstification is being installed under joint influence of tectonics, eustatism and climate. The endorheic basin of Issirac includes terrains from Cretaceous until Eocene age. Connected to the Alès groove, it has been undergoing eustatic variations combined with flows coming at the same time from the Cevennes and, apparently, from the installing endokarst in the regional carbonated platform englobing the plateau of Méjannes-le-Clap, located in the north of the Gard department, and the Cèze-Ardèche interfluvium. These observations underline a karstogenesis going back to late Cretaceous and early Paleogene times, related to the installation of a basin in conjunction with a planation surface in and on which redesigned sediments have been deposed of which, at present time, only relics remain. Nevertheless its poor visibility at the level of Paleocene and Eocene terrains of the Issirac basin, the karstogenesis permits to observe in the underlying limestone levels of the late Barrémian and Aptian (Bédoulian), indications of excavation whose infillings show strong proportions of alterites containing minerals of volcanic or magmatic origin coming from the Central Massif. The development of karstic aquiphers is orienting hypogeous drains towards successive base levels installing into the endorheic basin during the same periods, before their accomodations during Oligocene and Miocene times. This dynamic is modeling new endokarstic shaping of various gradations. The most recent geological in situ observations are indicating a progressive inversion of hypogeous drains changing from sedimentary base level aggradations formed by the endorheic basin of Issirac towards those of successive low levels related to the incision of Cèze and Ardèche rivers during Cenozoïc eras., Depuis l'émersion de la plate-forme carbonatée du bassin du Sud-Est de la France à l'époque de l'Albien-Cénomanien, un long processus de karstification complexe et polyphasé se met en place, sous les contraintes conjointes de la tectonique, de l'eustatisme et du climat. Le bassin endoréique d'Issirac comprend des terrains allant du Crétacé à l'Éocène. Connecté au sillon d'Alès, il a été soumis à des variations eustatiques combinées à des écoulements provenant à la fois des Cévennes et vraisemblablement de l'endokarst en cours d'édification dans la plate-forme carbonatée régionale qui englobe le plateau de Méjannes-le-Clap, situé au nord du département du Gard, et l'interfluve Cèze-Ardèche. Une karstogenèse s'instaure au Crétacé supérieur et au début du Paléogène. Elle est liée à l'installation d'un bassin et la formation d'une surface d'aplanissement où se déposent des sédiments remaniés dont il ne reste à ce jour que des reliquats. Peu visible au niveau des formations du Paléocène et de l'Éocène du bassin d'Issirac, la karstogenèse laisse entrevoir dans les assises calcaires du Barrémien supérieur et de l'Aptien (Bédoulien), des indices de creusement dont les remplissages contiennent en forte proportion des altérites présentant de minéraux d'origine volcanique ou magmatique en provenance du Massif Central. L'élaboration d'aquifères karstiques oriente des écoulements hypogés dirigés en premier lieu vers les niveaux de base successifs s'établissant dans le bassin endoréique au cours des mêmes périodes puis leurs accommodations au cours de l'Oligocène et du Miocène. Cette dynamique modèle des nouveaux façonnements endokarstiques de diverses ampleurs. Les dernières observations géologiques in situ mettent en exergue un changement de direction progressif des écoulements hypogés passant ainsi des aggradations sédimentaires du niveau de base constitué par le bassin endoréique d'Issirac à des points bas successifs liés à l'enfoncement des cours d'eau de la Cèze et de l'Ardèche durant l'ère Cénozoïque.

International audience; This study investigates the stratigraphic evolution of the Late Oligocene - Early Miocene carbonate platforms of the Yadana area (offshore Myanmar). Well data, regional 2D and local 3D seismic surveys allow the identification of three shallow-water carbonate platforms (Yadana, 3DF and 3DE) showing various morphologic and stratigraphic patterns influenced by the presence of a paleohigh. The identification of seven seismic sequences in the Yadana area constrains the stratigraphic evolution in three stages: (1) development of aggrading attached and isolated platforms during the Chattian; (2) a period of platform emersion during the Oligocene - Miocene transition; (3) drowning of the smaller buildup (3DE) associated with km-scale backstepping on the large platforms (3DF and Yadana) during the Aquitanian. The Aquitanian marks the onset of renewed volcanic activity associated with the development of fringing carbonate reefs during the Burdigalian. The rapid (similar to 6 My) development of these wide (similar to 5-70 km) and thick (similar to 300-850 m) carbonate platforms has been mainly controlled by the subsidence. However, the results highlight a strong overprint of eustatic fluctuations on the rates of change in accommodation, and hence on the stratigraphic architecture of the carbonate platforms. Based on an alternative model for the Cenozoic geodynamic evolution of the Yadana area, our results suggest that the platforms developed on a volcanic ridge of hotspot origin located in the Indian Ocean and not on a volcanic arc. Subduction jump processes are interpreted to have played a key role in the demise of all platforms by drastically changing the paleoenvironmental conditions during the Early Miocene, and led to the present-day location of the Yadana Ridge in a back-arc setting. The carbonate platforms from the Yadana area are thus a representative example of the interplay between global mechanisms and local paleoenvironmental parameters on carbonate platform initiation, growth and demise. (C) 2017 Elsevier Ltd. All rights reserved.

International audience; L’étude de l’impact des changements climatiques passés sur le domaine continental permet de comprendre les vitesses et le calendrier des changements d’écosystèmes liés aux perturbations. Leur compréhension nécessite une bonne connaissance des compartiments impliqués dans le système climatique (biosphère, hydrosphère, atmosphère), et ce à plusieurs échelles (climat global, régional et local). Ceci suppose de comprendre les mécanismes connectant ces compartiments tels que les transferts d’énergie, les couplages et les rétroactions, ainsi que par la détermination de la contribution des facteurs forçants naturels (intrinsèques : tectonique, PCO2 et extrinsèques : forçage orbitaux). Afin de déterminer la part des différents facteurs forçants et d’élucider l’ensemble des mécanismes, il paraît pertinent d’étudier de tels changements dans des systèmes climatiques radicalement différents de l’Actuel ou lors de transitions majeures. Le Cénozoïque se prête bien à ce type d’étude car la configuration géographique est relativement proche de l’Actuel. Par ailleurs, c’est au cours de la transition entre l’Eocène et l’Oligocène (TEO) que le mode climatique icehouse remplace le mode greenhouse, avec le développement de la première calotte permanente, ce qui a eu pour conséquence de nombreuses perturbations en domaine océanique et continental.Nous disposons d’un enregistrement sédimentaire lacustre de très bonne qualité (forage CDB1, CINERGY, BRGM) dans lequel les évolutions de la végétation ne montrent pas de changement notable à la TEO, mais l’existence d’un intervalle de transition (IT) caractérisé par des changements rythmiques de la végétation, dont la fréquence est proche de celle de la grande excentricité. Les évolutions des températures montrent deux principaux refroidissements, dont un coïncidant avec la limite Eocène-Oligocène. L‘évolution des conditions hydrologiques montre également des changements entre des périodes humides puis sèches au début de l’IT, des conditions humides durant la limite EO et le retour à des conditions sèches à la fin de l’IT. Bien que cet IT soit à la fois marqué par des conditions climatiques remarquables et des successions de végétation rythmées, aucune corrélation directe n’a pu être établie entre végétation et climat. Ceci suggère la mise en place, pendant cet IT, de mécanismes complexes tels que la saisonnalité, sous contrôle d’oscillations climatiques d’échelle globale tel que les couplages océans-atmosphère (Ghirardi et al., 2015).Les paramètres orbitaux filtrés du signal Gamma-Ray montrent d’importants changements d’amplitude le long de l’enregistrement. Un premier changement majeur de l’amplitude de l’excentricité coïncide avec la limite inférieure de l’IT. Un second changement d’amplitude est enregistré à la fin de l’IT. La latitude du site n’ayant pas radicalement évoluée sur la période considérée, les changements d’amplitude de l’excentricité suggèrent la mise en place de transferts latitudinaux d’énergie au début de l’IT et la transition entre les modes greenhouse et icehouse à la fin de l’IT. La mise en place d’un courant océanique de type proto-Gulf Stream (Wade et al., 2003) ou des pulsations de la « North Circulation Water » (Wright and Miller, 1996), permettraient d’expliquer ces transferts d’énergie. La mise en place de tels courants est liée à des couplages océan-atmosphère entraînant des oscillations climatiques haute fréquence décennales à saisonnières de type North Atlantic Oscillation. Nous avons donc entrepris l’étude haute fréquence des lamines sédimentaires afin de détecter de telles variabilités. Les analyses de la distribution organique et minérale à très haute fréquence par spectromètre de masse à temps de vol secondaire (ToF-SIMS) indiquent que les plus petites lamines ont des épaisseurs de 30 à 50 µm. L’analyse spectrale de la distribution en éléments majeurs (Fe, Al, Si) issus de mesures haute fréquence par XRF-Core Scanner montre que les plus petites lamines se sont déposées en 3 ans et que des cycles proches des fréquences solaires (11 et 22 ans) semblent être enregistrés. L’étude basse fréquence des évolutions de la végétation, du climat local, et des amplitudes des paramètres orbitaux, combinée à l’analyse très haute fréquence du sédiment laminé de part et d’autre de l’intervalle de transition, devrait permettre d’apporter de nouveaux éléments sur la mise en place de mécanismes régissant le climat actuel (Gulf Stream, NAO), de discuter la vitesse de la transition climatique et le calendrier des changements enregistrés en domaine continental. Ghirardi et al., 2015. Résumé ASF 2015Wade et al., 2012. Geology 40, 159–162.Wright and Miller, 1996. Paleoceanography 11, 157– 170.

International audience; An innovative multidisciplinary approach was used on quartz–calcite veins that crosscut pebbles of several lithologies from the French South Alpine Foreland Basin to discern the source of detrital sediments. Microthermometric results indicate that inclusions contain low to moderate salinity (0.9–9.8 wt% eq. NaCl) fluids. Oxygen and carbon isotope compositions of quartz and calcite (δ18O mean at +24.1 and +24.7 ‰ respectively (V-SMOW) and δ13C from −1.1 to +2.0 ‰ (V-PDB)) are comparable with the composition of their host rocks (δ18O from +17 to +24.3 ‰ and δ13C from −4 to +1.4 ‰). The calculated δ18O and δ13C values of the fluid trapped in quartz and calcite range from +9.3 to +21.9 ‰, and from −2.6 to +4.1 ‰ respectively. These data suggest isotopic buffering of the fluid by the host rocks. Fluid trapping conditions were 105–185 MPa and 175–310 °C. Using a lithostatic gradient, the conditions of fluid entrapment correspond to a depth of vein formation from 4 to 7 km. Petrographic and geochemical data obtained on the host rocks, their veins and fluid inclusions suggest that the source of the conglomerates is the inner part of the Alps rather than reliefs surrounding the foreland basin. The study of fluid inclusions in veins provides a powerful and innovative approach to link the production of detrital sediments with tectonic events, to trace the provenance of conglomerates and to reconstruct the regional geometry of the drainage system.

A new assemblage of ruminants from five distinct Oligocene localities of the Kizilirmak Formation, Central Anatolia, Turkey is described. The tragulids Iberomeryx parvus, and Iberomeryx sp. (large), as well as a probable large lophiomerycid have been recognized. The stem pecoran Dremotherium guthi, cf. Palaeohypsodontus and a large indeterminate Pecora have been identified as well. In the five localities, the majority of the ruminant material is referred to Iberomeryx parvus, but the sample from the locality Tepe 641 (upper member of the Kizilirmak Formation) shows some distinctive characters suggesting a more derived species/forms that probably lived in more open environments. The ruminant taxa recorded in the Kizilirmak Formation are congruent with a Late Oligocene age, probably close in age to the Benara fauna of southern Georgia. The possible occurrence of Palaeohypsodontus in Central Anatolia would significantly expand its geographical range and suggest biogeographical affinities with Central Asia. The ruminant fauna from the Kizilirmak Formation suggests the existence of lowland forests with more open landscapes in central Anatolia during the Late Oligocene.

Las cuencas de Marsella-Aubagne, que se extienden desde Marsella a Roquevaire, ocupan más del cin¬cuenta por ciento del mapa geológico de Marsella-Aubagne con cerca de un millón de personas viviendo en la región. A pesar de su importancia geológica, aún son poco conocidas. La primera visión sintética fue llevada a cabo en el mapa geológico de 1935. Estudiados por Bonifay, los depósitos cuaternarios fueron incluidos en el mapa geológico de 1969. Sin embargo, las formaciones del Oligoceno no se modificaron hasta que Nury proporcionó una gran cantidad de datos estratigráficos muy detallados. Nuevos estudios han sido llevados a cabo en el marco de la tercera edición del mapa geológico 1:50 000. Estos estudios per¬miten distinguir entre tres cuencas diferentes: la «cuenca de Jarret» en la parte norte, la «cuenca del Prado» en la parte suroeste y la «cuenca de Aubagne» en la parte oriental. Cada una de ellas contiene su propia sucesión estratigráfica que incluye varias formaciones desde el Rupeliense hasta el Chattiense. De manera general, las formaciones del Rupeliense inferior a superior están deformadas tectónicamente, mientras que los depósitos del final del Rupeliense hasta el Chattiense superior sólo presentan una deformación leve. Por lo tanto, se han podido diferenciar dos etapas geodinámicas principales: la primera empieza con régimen distensivo en el Oligoceno inferior y conduce a la apertura de depresiones de dirección NNE-SSO a lo largo de toda la plataforma europea y, la segunda, que comienza con un régimen distensivo NNO-SSE coetáneo con el rifting del Mediterráneo Occidental. El punto clave que separa estas dos fases entre sí es un posible régimen compresivo en el Rupeliense más tardío. Para concluir, esta cuenca se puede utilizar como un archi¬vo natural para los eventos del Oligoceno. Por lo tanto, estas cuencas deben ser consideradas como piezas maestras para las reconstrucciones paleogeográficas y geodinámicas del Oligoceno. The Marseille-Aubagne Basins, which extend from Marseille to Roquevaire, occupy more than fifty per cent of the Marseille-Aubagne geological map, with approximately one million people living in this area. Despite this geological importance they are still poorly known. The first synthetic view was delivered in the 1935 geological map. Studied by Bonifay, the Quaternary deposits have been included in the 1969 geological map. Nevertheless, the Oligocene formations remained unmodified until Nury, who provided a lot of very detailed stratigraphic data. New studies have been carried out in the frame of the third issue of the 1:50,000 geological map. These studies allow us to distinguish between three different basins: the “Jarret basin” in the northern part, the “Prado basin” in the southwestern part and the “Aubagne basin” in the eastern part. Each of them contains its own stratigraphic succession, including several formations from the Rupelian to the Chattian. Globally, the Lower to Upper Rupelian formations are tectonically deformed, whilst deposits from the Latest Rupelian to the Latest Chattian show only slight deformation. Thus, two main geodynamic stages have been distinguished: the first beginning with the Early Oligocene extensive regime leading to the opening of NNE-SSW troughs all over the European platform and, the second, beginning with a NNW-SSE extensive regime coeval with the Western Mediterranean rifting. The key point that separates these two stages from each other is a possible Late Rupelian compressive regime. To sum up, this basin can be considered as a natural archive for the Oligocene events. Therefore, these basins should be considered as master pieces for the Oligocene palaeogeographic and geodynamic reconstructions.

Anomaluroid rodents show interesting biogeographic and macroevolutionary patterns, although their fossil record is meager and knowledge of the natural history of extant members of the clade remains inadequate. Living anomaluroids (Anomaluridae) are confined to equatorial parts of western and central Africa, but the oldest known fossil anomaluroid (Pondaungimys) comes from the late middle Eocene of Myanmar. The first appearance of anomaluroids in the African fossil record coincides with the first appearances of hystricognathous rodents and anthropoid primates there. Both of the latter taxa are widely acknowledged to have originated in Asia, suggesting that anomaluroids may show a concordant biogeographic pattern. Here we describe two new taxa of African Paleogene anomaluroids from sites in the Sirt Basin of central Libya. These include a new Eocene species of the nementchamyid genus Kabirmys, which ranks among the oldest African anomaluroids recovered to date, and a new genus and species of Anomaluridae from the early Oligocene, which appears to be closely related to extant Zenkerella, the only living non-volant anomalurid. Phylogenetic analyses incorporating the new Libyan fossils suggest that anomaluroids are not specially related to Zegdoumyidae, which are the only African rodents known to antedate the first appearance of anomaluroids there. The evolution of gliding locomotion in Anomaluridae appears to conflict with traditional assessments of relationships among living anomalurid taxa. If the historically accepted division of Anomaluridae into Anomalurinae (extant and Miocene Anomalurus and Miocene Paranomalurus) and Zenkerellinae (extant and Miocene Zenkerella and extant Idiurus) is correct, then either gliding locomotion evolved independently in Anomalurinae and Idiurus or non-volant Zenkerella evolved from a gliding ancestor. Anatomical data related to gliding in Anomaluridae are more consistent with a non-traditional systematic arrangement, whereby non-volant Zenkerella is the sister group of a clade including both Anomalurus and Idiurus. Kabirmys prius: urn:lsid:zoobank.org:act:C4FC0114-DAA6-4D12-BD3C-F5900BE1AD1E Prozenkerella: urn:lsid:zoobank.org:act:144DC508-333F-4746-A313-A0556804D7F1 Prozenkerella saharaensis: urn:lsid:zoobank.org:act:76992C9D-D754-40E9-B8E2-E786A5BC7E8C urn:lsid:zoobank.org:pub:866B8A65-BCB2-4E8F-B6FA-24637606528C

Les restes d'oiseaux de Valbro appartiennent seulement à trois espèces, Paraortyx lorteti, Archaeotrogon venustus et A.~zitteli. Cette association permet d'attribuer à cette avifaune un âge Oligocène inférieur, niveaux-repères MP~22~ou MP~23, ce qui correspond bien avec l'âge indiqué par les mammifères. The bird remains from Valbro belong only to three taxa, Paraortyx lorteti, Archaeotrogon venustus, and A.~zitteli. This association makes it possible to ascribe to this locality an early Oligocene age, reference-levels MP 22~or MP 23, which is in agreement with the age given by the mammals.

WOS: 000332444900003, The Sivas basin (Turkey) shows pronounced salt tectonics activity involving the Oligocene evaporites. Despite the complete exposure of the structures, the tectonic evolution of the basin has been so far misunderstood because it has only been envisioned in a context of thrust tectonics. The core of the basin, a 35x25 km area, displays rounded minibasins separated by evaporitic walls, and partially covered by remobilized gypsum (either sedimentary or flowage). The minibasins are filled by Mid-Oligocene to Early Miocene clastics (fluvial silts and sandstones), marls, and lacustrine to marine limestones, the thickness of which may reach 4 kilometres. The stratal architecture along evaporite walls records the progressive subsidence of the minibasins, with strong rotation of beds, unconformities and local reworking of evaporites. Within the basin, the sediments show lateral thickness variations and spectacular angular unconformities. The observed geometries show striking similarities with the seismic data from petroleum basins suffering strong salt tectonism (gulf of Mexico, Precaspian basin, Angolan margin)., Total SA; Total SA "Structural geology Chair" at University of Pau and Pays de l'Adour; Cumhuriyet University, We thank Total SA for financial support. J.-P. Callot acknowledges a grant from Total SA "Structural geology Chair" at University of Pau and Pays de l'Adour. Cumhuriyet University is warmly thanked for their support and help during field work. J.-F. Salel and V. Martin (Cobalt Energy) helped in retrieving seismic data. M. Jackson, M. Hudec, B. Vendeville, an anonymous reviewer and editor O. Lacombe are warmly thanked for their pertinent reviews. The field party is acknowledge: C. Mallard, A. Pichat, E. Legeay, R. Graham, J. Letouzey, A. Rouchy, G. Hoareau, E. Surmeli, M.F. Surmeli, T. Kus, F. Birol, N. Keskin, S. Emrahoglu.

International audience; The locality Valbro (Quercy, France) has yielded a rich fossil vertebrate fauna. Here are presented the geological context, a preliminary faunal list and the systematics of the Rodentia and carnivores, the most abundant taxa of the fauna. The Rodentia are known from 11 taxa: the Theridomyidae Blainvillimys grega-rius Schlosser, 1884, Blainvillimys ?gemellus Vianey-Liaud, 1989, Issiodoromys medius (Vianey-Liaud, 1976)and S. cayluxi Schlosser, 1884, the Aplodontidae Plesispermophilus angustidens Filhol, 1882, the GliridaeButseloglis tenuis (Bahlo, 1975), Butseloglis micio (Misonne, 1957) and Bransatoglis planus (Bahlo, 1975), theSciuridae Palaeosciurus goti Vianey-Liaud, 1974 and cf. Oligopetes sp., and the Cricetidae Atavocricetodonsp. aff. A. nanus (Pelaez-Campomanes, 1995). Thirteen taxa of carnivores are present at Valbro; amongthe Hyaenodontida: Hyaenodon leptorhynchus Laizer et Parieu, 1838 and cf. Apterodon sp.; among the Car-nivora: a Feliformia gen. et sp. indet., the Nimravidae Nimravus intermedius (Filhol, 1872), Dinailurictisbonali Helbing, 1922 and Nimravidae gen. et sp. indet. (Certainly belonging to one the two already iden-tified species), the Ursida Pachycynodon crassirostris Schlosser, 1888, Pachycynodon sp., Amphicynodonsp. 1 cf. A. typicus (Schlosser, 1888), Amphicynodon ? sp. 2 and Ursida gen. et sp. indet. cf. Pachycynodonboriei (Filhol, 1876), the Mustelida M. olivieri Bonis, 1997, the Carnivora incertae sedis Palaeogale sectoria(Gervais, 1848–1852), the Arctoidea gen. et sp. indet. and Carnivora gen. et sp. indet. (probably represen-ting taxa already identified at lower taxonomic levels). The evolutionary grade of B. gregarius of Valbrocompares to that of the species from Mas de Got, La Plante 2 and Cavalé, which supports an MP22 agefor Valbro. This datation is further supported by the association of Theridomyinae yielded by the locality(B. gregarius, B. gemellus, I. medius and S. cayluxi), and by the presence of a N. intermedius that well comparesthe material of the species from Villebramar, La Plante et Mas de Got, of D. bonali, P. sectoria, M. olivieri(species known only from Mas de Got), and by additional evidence from the remaining vertebrates fromValbro, especially the squamates. Despite a limited amount of specimens (341 specimens have been stu-died), the faunas of rodents and carnivores from Valbro are the most speciose and diverse known for theMP22 level and, for the Carnivora fauna in particular, for the Oligocene of the Old World.; Le gisement de Valbro (Quercy, France) a livré une riche faune de vertébrés fossiles. Dans cette contribution sont présentés le contexte géologique, la liste faunique préliminaire et l’étude systématique des rongeurs et des carnassiers, les groupes dominants de cette faune. Les rongeurs sont représentés par 11 taxons : les Theridomyidae Blainvillimys gregarius Schlosser, 1884, Blainvillimys ?gemellus Vianey-Liaud, 1989, Issiodoromys medius (Vianey-Liaud, 1976) et Sciuromys cayluxi Schlosser, 1884,l’Aplodontidae Plesispermophilus angustidens Filhol, 1882, les Gliridae Butseloglis tenuis (Bahlo, 1975),Butseloglis micio (Misonne, 1957) et Bransatoglis planus (Bahlo, 1975), les Sciuridae Palaeosciurusgoti Vianey-Liaud, 1974 et cf. Oligopetes sp., et le Cricetidae Atavocricetodon sp. aff. A. nanus (Pelaez-Campomanes, 1995). Treize taxons de carnassiers sont présents à Valbro ; chez les Hyaenodontida :Hyaenodon leptorhynchus Laizer et Parieu, 1838 et cf. Apterodon sp. ; chez les Carnivora : le Feliformiagen. et sp. indet., les Nimravidae Nimravus intermedius (Filhol, 1872), Dinailurictis bonali Helbing, 1922 etNimravidae gen. et sp. indet. (représentant certainement l’une des deux espèces identifiées), les UrsidaPachycynodon crassirostris Schlosser, 1888, Pachycynodon sp., Amphicynodon sp. 1 cf. A. typicus (Schlosser,1888), Amphicynodon ? sp. 2 et Ursida gen. et sp. indet. cf. Pachycynodon boriei (Filhol, 1876), le Muste-lida Mustelictis olivieri Bonis, 1997, le Carnivora incertae sedis Palaeogale sectoria (Gervais, 1848–1852),l’Arctoidea gen. et sp. indet. et Carnivora gen. et sp. indet. (représentant vraisemblablement un taxon identifié à un rang taxonomique inférieur). Le stade évolutif du B. gregarius de Valbro, comparable à celui de l’espèce provenant de Mas de Got, La Plante 2 et Cavalé rapproche Valbro du niveau MP22 (Oligo-cène inférieur). Cette datation est renforcée par l’association des Theridomyinae rencontrés dans legisement (B. gregarius, B. gemellus, I. medius et S. cayluxi), par la présence d’un N. intermedius au stade évolutif comparable à celui de l’espèce de Villebramar, La Plante et Mas de Got, de D. bonali, P. sectoria,M.olivieri (espèce connue uniquement de Mas de Got), ainsi que par les autres éléments de la faune,notamment les squamates. Malgré un matériel fossile restreint (341 spécimens étudiés), les faunes de rongeurs et de carnassiers de Valbro sont d’une diversité et d’une richesse sans équivalent pour le niveauMP22 et, pour la faune de Carnivora en particulier, sans équivalent pour l’Oligocène de l’Ancien Monde.

International audience; Entre 1966 et 1980, une polémique a opposé deux géologues quelque peu marginaux aux spécialistes de la biostratigraphie des mammifères et de la tectonique provençale. Cette controverse entre des protagonistes de statuts différents a faussé le développement d’une intéressante discussion concernant l’âge, soit éocène inférieur, soit oligocène inférieur, d’un ensemble de dépôts isolés dans des synclinaux et fossés de l’intérieur de la Provence. Ce sont les derniers terrains affectés par une intense tectonique de chevauchements que l’on doit rattacher soit à une phase de serrage pyrénéo-provençale (éocène) qui n’aurait eu qu’une extension limitée, soit à une phase post-oligocène que l’on peut qualifier d’alpine. Le contexte éditorial de cette époque était particulièrement favorable, grâce à l’activité de la Société géologique de France, qui ouvrait alors ses portes et ses colonnes aux discussions. Les découvertes de mollusques continentaux par Fernand Touraine et leur identification par RogerRey comme caractéristiques de l’Oligocène inférieur ont donc été confrontées publiquement à celles de restes de mammifères de l’Éocène inférieur, soit isolés, soit en nombre (dans le riche gisement très localisé de Rians). Le conflit qui a opposé l’interprétation de l’origine autochtonedes mammifères et, par conséquent, de l’âge éocène des dépôts qui les contenaient, à celle de leur remaniement à l’Oligocène (Touraine), a été déplacé vers une opposition entre la valeur stratigraphique respective des vertébrés et des mollusques. Les multiples arguments réunis parTouraine, à l’aide d’organismes différents, ont été écartés et les indices sédimentaires n’ont pas été pris en compte, au point que les riches débats publics n’ont abouti qu’au refus de prendre une décision. Cette indécision a été diffusée comme la seule conclusion acceptable… jusqu’en2012. Notre étude réunit les arguments pour un âge oligocène qui ont été négligés, y compris ceux qui ont été ajoutés après la disparition des trublions (en 1978 et en 1980). L’intérêt historique de l’analyse détaillée de cette controverse réside surtout dans la comparaison entre lecontexte d’organisation et de diffusion des débats, qui caractérise les premières décennies de la deuxième moitié du XXe siècle en France, et celui qui résulte d’une volonté d’adaptation à la mondialisation de la recherche en géologie, apparue avant la fin de ce siècle. L’évolution de laplace des géologues amateurs dans la recherche géologique régionale est abordée en conclusion.

The aim of this dissertation was to use a multidisciplinary approach, combining petrologic, geochemical and geo-thermochronologic analyses, to reconstruct the topographic and exhumational evolution of the Western Alps during Oligocene and Early Miocene times, in relation to regional geodynamic events. Because the sedimentary record of this evolution is preserved in the foreland basins on the both sides of the Western Alps in France and Italy, this approach allows identifying sediment provenance and exhumation rates in the drainage areas. Petrological analyses used here were macroscopic observations in the field (pebbles counts), thin section analyses, and Raman spectrometry on detrital serpentinite pebbles and serpentine sand grains. The different serpentine species (antigorite, lizardite etc.), can be traced back to specific source lithologies because the metamorphic grade of the rocks exposed in the Western Alps increases eastward, with antigorite (HT serpentine) bearing rocks in the eastern piedmont complex and mixed lizardite-antigorite (LT serpentine) in the western piedmont complex. Analysis of serpentine species in the foreland basin deposits on both sides of the Alps allows determining changes in the paleo-Durance and paleo-Dora Riparia drainage areas and the position of the drainage divide, which have not changed since the Early Miocene. Major and trace element analyses of non-metamorphic basalt pebbles from the Barrême basin hint at the Chenaillet (or equivalent) obducted ophiolite in the internal Western Alps as the most likely source. Fission-track (FT) analysis of detrital apatite and zircon were used to determine maximum and average exhumation rates during the Oligocene. A pulse of fast erosional exhumation at about 30±1 Ma had rates on the order of 1.5-2 km/Myr, while average rates were about 0.2-0.3 km/Myr. FT and U/Pb double dating of single zircons show that the signal of fast exhumation is not an artifact caused by volcanic contamination at around 30 Ma. The rapid creation of high relief and associated exhumation rates are related to isostatic surface uplift after slab break-off beneath the Western Alps at 35-30 Ma, followed by slab retreat which allowed emplacement of the Ivrea body vertical indenter that supports the high topography in the internal Western Alps., Le but de cette thèse est l'utilisation d'une approche multidisciplinaire qui combine des techniques d'analyse pétrologique, de la géochimie et de la thermochronologie afin de reconstituer l'évolution des Alpes occidentales pendant l'Oligocène et le Miocène et d'en déduire les implications géodynamiques. Ces techniques permettent à la fois d'identifier le bassin de drainage des sédiments et les taux d'exhumation dans ce bassin de drainage. L'enregistrement de cette évolution est préservé dans les bassins d'avant pays de chaque côté des Alpes occidentales en France et en Italie. Les techniques d'analyse pétrologique utilisées ici sont l'observation macroscopique, l'observation en lames minces, l'analyse par spectromètre Raman et l'étude de minéraux lourds. De nombreuses études ont été réalisées afin d'analyser les minéraux lourds des bassins alpins. Celles-ci permettent de déterminer la provenance des minéraux. Lors de ce projet, nous avons réalisé des analyses Raman sur des serpentinites permettant de distinguer les différents types de serpentinites. Or les Alpes internes montrent une gradation du métamorphisme croissant vers l'est, qui implique une variation des types de serpentinites vers l'est (association lizardites et antigorites dans les zones de basse température, antigorites exclusivement dans les zones de haute température). L'analyse de l'arrivée des différents types de serpentinites de part et d'autre de la chaîne permet de définir la position des réseaux de drainage dans les Alpes internes et de positionner la ligne de partage des eaux. La géochimie sur les basaltes détritiques permet d'analyser le type de basaltes et donc d'identifier leurs sources. Des basaltes non métamorphiques ont été identifiés en quantité importante dans les bassins d'avant-pays côté français démontrant la répartition importante de matériels océaniques obduits sur les Alpes internes à l'Oligocène. Les âges de thermochronologie détritique comparés à l'âge de dépôt permettent de déterminer le lag-time et donc le taux d'exhumation maximum de la zone érodée. En effet, la modélisation des isothermes permet de déterminer un taux d'exhumation à partir du lag-time. L'analyse des taux d'exhumation le long de la colonne stratigraphique à Barrême montre un pulse d'exhumation à partir d'une période très brève dans le temps : 30±1 Ma à des taux d'exhumation compris entre 1,5 à 2 km/Ma, qui correspond à la mise en place des Alpes internes. Ces taux d'exhumation correspondent à des taux d'exhumation importants mais inférieurs à ce que l'on peut trouver dans l'Himalaya actuellement. Ils sont toutefois comparables à l'activité d'exhumation dans des montagnes jeunes. De récents travaux de modélisation montrent que le retrait de slab peut être consécutif à une rupture de slab profond. Notre équipe propose que dans les Alpes occidentales, la rupture et le retrait de slab a permis la mise en place du corps d'Ivrea comme un poinçon au dessus du slab.

International audience; For the first time in the Western Alps, radiolarite pebbles collected from Tertiary foreland molasse conglomerates are treated for microfossil extraction and dated. Among forty pebbles collected in the field, seven of them released diagnostic radiolarian assemblages ranging in age from Late Bajocian-Early Callovian to Middle Oxfordian-Early Tithonian. These ages overlap previous biochronological data obtained from in situ localities of the Schistes Lustres Piemont zone of the French-Italian Alps and triple the number of diagnostic radiolarite samples known so far in this segment of the chain. The diagnostic pebbles are characterized by low grade metamorphism, showing that some eroded thrust-sheets from the oldest parts of the ocean escaped any tectonic burial during the Alpine convergence. Mixing of low and high-grade radiolarites, mafics and ultramafics pebbles implies that various ocean-derived units were exposed. This tectonic scenario involves tight refolding and severe uplift of the Eocene subduction wedge in the Early Oligocene.

International audience; Zooxanthellate-coral (z-coral) generic richness values from 102 Oligocene-Miocene localities from the Mediterranean and adjacent areas are tested in this paper as a proxy for relative palaeotemperatures, essentially using the quantitative relationship between taxonomic richness and prevailing seawater temperature underlined by the so-called ‘energy hypothesis’. Patterns of generic richness and inferred palaeotemperatures are examined for each stage of the Oligocene-Miocene time interval and compared with some global palaeoclimatic curves based on oxygen stable-isotopes. Except for the Mid- Miocene Climatic Optimum, which is not recorded in the generic richness of the Mediterranean z-coral communities, the coral-richness-derived palaeotemperatures correlate well with the general palaeoclimatic trends shown by the isotope curves. Results also show: (1) a gradual increase of temperature from the early to the late Rupelian; and (2) a gradual widening of the temperature range after the Burdigalian. The latter indicates that z-coral communities were able to maintain themselves in the region by progressively adapting to a wider temperature range from the mid-Miocene onwards to the Messinian, as the Mediterranean was migrating northward. Although limitations and biases are underlined and discussed in the paper, the ‘energy hypothesis’ applied to fossil z-coral faunas appears to offer a powerful method when used at global or regional scales to estimate changes in palaeotemperatures. It holds particular promise for time intervals and regions where conventional isotopic data are lacking, such as the Oligocene and Miocene of the Mediterranean.

International audience; Reefs, especially tropical coral reefs, are commonly thought to be highly sensitive to climate change. The relationship between Cenozoic reef distribution, as recorded in the PaleoReefs database, and palaeoclimatic change, as inferred from geological and geochemical proxies, has been tested. The focus is on the Oligocene-Miocene transition, but the entire pre-Pleistocene Cenozoic reef distribution was analyzed to put the results into a broader context. It is found that reef distribution patterns are not cross-correlated with palaeoclimate change. If anything, the global cooling trend from the Eocene to the Miocene is correlated with an increase of reef carbonate production and a latitudinal expansion of the reef belt, rather than the expected opposite. This reef - climate paradox is best explained by a combination of two end-member hypotheses: (1) a macroevolutionary shift led from an extrinsic control (i.e. climate-driven) on reef development during the early Palaeogene greenhouse, to an intrinsic control (i.e. biological adaptation to new oceanographic and nutrient conditions) in the late Palaeogene-Neogene icehouse; and (2) the deleterious effects of climatic cooling on reef building were made up by changes in oceanography that led to a reduction of equatorial upwelling, and an increase of habitat area of low-nutrient shallow-water settings favourable for zooxanthellate coral reef growth.

International audience; During the Oligocene–Miocene Greenhouse-to-Icehouse climatic transition, the biogeography of reef corals or zooxanthellate-like scleractinian corals was gradually changing from a pan-tropical Tethyan Province in the Eocene to three reef-coral Provinces of the Western Atlantic–Caribbean, Indo-Pacific and Mediterranean.Our REEFCORAL database encompasses updated and homogenized data on paleoenvironmental and systematics of scleractinian corals occurring in the Oligocene and Miocene outcrops from circum-Mediterranean regions, provided by most of relatively recently published data in the literature and by the study of published and unpublished collections of coral specimens from the same area, including the important collections housed at the MNHN (Paris) and our own collections. As there is no validated direct criterion for the identification of the coral-zooxanthellate symbiosis in the fossil record, and considering the difficulty to use the biogeochemical approaches in the context of this study, the subjectivity of the morphological criteria and the relative recent age of the fossil corals we are dealing with, a uniformitarian approach has been used for inferring the symbiotic status of scleractinian genera in REEFCORAL. Among the 158 genera included in our database, 93 can be considered as zooxanthellate and 10 have a doubtful zooxanthellate status. This relatively exhaustive database was used to reconstruct the temporal and spatial distribution of scleractinian corals in the Mediterranean during the Oligocene–Miocene time in order to discuss the interplaying effects of the global cooling at that time, the re-organization of the Tethyan realm resulting from the African, Arabian and Eurasian plate collision and the emergence of the Alpine chains, driving the gradual northward movement of the whole region outside the tropical/subtropical belt.It is shown that the structure of the Mediterranean z-coral Oligocene–Miocene paleobiodiversity was characterized by many geographically-restricted genera with a moderate to short stratigraphical range and a few long-ranging widespread genera. A major consequence of this structure is that the extinction pattern has proceeded through the preferential extinction of rare-occurrence genera through time. The potential rapid long-distance dispersal of most coral larvae compared to the size of the Oligocene–Miocene Mediterranean, explains why no biogeographical subprovinces can be distinguished for the z-coral fauna. On a local scale, ecological processes tend to sort coral taxa by limiting z-coral development to geographically restricted and discontinuous areas. This accounts for the large amount of geographically-restricted taxa forming the Mediterranean coral fauna.The interaction of plate-tectonics, Alpine orogenesis and climate at local to subregional scales exerts strong controls over the spatio-temporal distribution of z-coral assemblages within the circum-Mediterranean realm. In particular, we suggest that the richness and composition of the Eastern Atlantic coral fauna are indirectly related to the opening and closure of the eastern seaway connection with the Indian Ocean, which controlled the E–W circulation of surface waters and hence the westwards dispersal of pelagic larvae. At the scale of the whole region, the gradual regional climatic change produced by the northwards migration of the entire area, superimposed on the global cooling, appears in large part responsible for the extinction pattern of z-corals through time in the Mediterranean biogeographical Province.

International audience; The feeding apparatus of Paleogene birds is rarely well-preserved. Here, we describe the earliest known pelican (early Oligocene, Luberon, southeastern France), with its almost complete beak. Morphologically identical to modern pelicans, the new fossil already shows several advanced features unique to extant species of the genus Pelecanus. It probably belongs to the lineage ancestral to all or some of these pelican species. This fossil reveals a remarkable evolutionary stasis in the morphology of such an advanced avian feeding apparatus through ca. 30 million years. Several hypotheses are proposed to suggest explanations for such examples of long stases in volant homeothermic vertebrates.

In the western Mediterranean Sea, the Liguro-Provençal Basin (LPB) is a key area for studying passive margins because of its recent formation and abundance of onshore and offshore data. The Nerthe area located in the northern margin of LPB provides the unique continuous Oligo-Miocene deposits contemporaneous of the transition rifting to drifting. However, the age of the deposits remains debated and the link between outcrops and offshore seismic data is poorly constrained. The purpose of this paper is double. First, we intend to propose a new chronostratigraphic frame based on bio- (planktonic foraminifera, calcareous nannofossils) and magneto-stratigraphy. Second, we aim to make, through the integration of new highly time-resolved seismic data and field works, a coherent onshore-offshore link concretized by a 3D geological model. The new temporal and spatial data presented in this paper allow correlating the Oligo-Miocene sequences, defining their geometry and specifying precisely the timing of syn- and post-rift stages. The first marine transgression is now precisely dated latest Chattian within the syn-rift deposits and appears to be synchronous with the first marine deposits in the offshore wells and other marginal basins. The transition from syn-rift to post-rift appears to last 3.3 Ma at maximum, between 21.8 and 18.5 Ma (late Aquitanian to early Burdigalian). It is underlined by two major erosional unconformities bearing a hiatus of around 1 Ma. The post-rift started with a major marine transgression that is now dated from middle Burdigalian, at around 18.5 Ma, as elsewhere in the LPB. Contrarily to recent proposals, the post-rift deposits are widely represented on the northeastern margin of the “Golfe du Lion”. There, the subsidence of the margin was low during the syn-rift and the transitional periods and high during the post-rift. The onset of this high post-rift subsidence appears to be synchronous with the slowdown of the Corsica-Sardinia block (CSb) motion.

International audience; The Arizpe sub–basin located in the northern part of the Río Sonora basin is a Basin and Range half–graben that initiated during Late Oligocene time in north–central Sonora. Its ~2.1 km–thick, east–dipping volcanic and sedimentary fill assigned to the Báucarit Formation is divided, from base upwards, into the following informal members. The La Cieneguita member composed ofinterbedded conglomerate, siltstone and gypsum beds which unconformably overlay older Cenozoic volcanic rocks; the El Toro Muerto basalt composed of basaltflows, basalt breccia and subordinate conglomerate beds; the Arzipe conglomerate composed of three fining–upwards conglomerate sequences that interdigitates with flows of the Tierras Prietas basalt in its lower part and the Agua Caliente basalt in its upper part; the Bamori member is a coarsening–upward succession of siltstone, sandstone and conglomerate that unconformably overlies the Arizpe conglomerate and it is unconformably overlain by the sedimentary El Catalán breccia. Basin accommodation started at ~25 Ma when deposition of the La Cieneguita member, followed by alkaline basaltic volcanism of the El Toro Muerto and contemporaneous rhyolitic volcanism, floored the area predating significant clastic deposition. The Agua Caliente basalt (~21 Ma) in the upper part of the basin fill indicates the basin was rapidly subsiding. Multiple phases of normal faulting affected the Arizpe sub–basin. The main controlling structure may be the steep (80°), west–dipping, sub–parallel El Fuste and Granaditas normal faults that bound the Arizpe sub–basin at its present–day eastern margin, or there may be afault orfaults that were subsequently buried beneath younger basin fill near the eastern margin of the basin. The basin was disorganized by an even younger NW–SE phase of normal faulting represented by the southwest–dipping Crisanto and Tahuichopa faults. Growth strata within basin fill suggests that syntectonic deposition was active during all phases of normal faulting. However, punctuated tectonic activity on these faults may have controlled deposition of conglomerate sequences of the Arizpe conglomerate. Geochemical data from the El Toro Muerto, the Tierras Prietas and the Agua Caliente basalt members indicate they are high–K, alkaline to subalkaline basaltic trachyandesites with light REE–enriched patterns, initial Sr ratios between 0.7069 and 0.7076, and εNd values between –3.76 and –4.88. Pb isotopic values from two samples of the El Toro Muerto basalt yielded very similar results, and along with the other geochemical data suggest an important participation of the continental lithosphere as magma source for this volcanism. The data herein reported are supported by eight new geochronologic ages and they contribute to better document and constrain the timing of magmatism and extension in the Basin and Range tectonic province in Sonora.

Twelve mollusk species from late Jurassic to Oligocene cold seep deposits are described and illustrated. Nine of them are new, two have already been named, two new genera are introduced, and one species is described only in open nomenclature. Puncturella (sensu lato) mcleani sp. nov. and Fissurella (sensu lato) bipunctata Stanton, 1895 are the only confirmed fissurellids in fossil cold seeps. The sutilizonid Triassurella goederti sp. nov. is similar to the modern ventinhabiting Sutilizona and the Late Triassic shallow-water reef-inhabitant Triassurella carnica. A smooth, late Jurassic neritid is the oldest neritid from fossil seeps and probably represents an independent neritid radiation into the seep environment, without close phylogenetic connection to the modern Bathynerita. The four new abyssochrysoid caenogastropods Humptulipsia macsotayi, Hokkaidoconcha novacula, Paskentana anistratenkorum, and P. umbilicata significantly extend the stratigraphic and geographic ranges of these apparently seep-restricted genera. Four bivalves are described, including the new modiomorphid Caspiconcha rubani from the early Cretaceous and the new bathymodioline Bathymodiolus (s.l.) palmarensis from the Oligocene. Among the lucinids, the oldest seep-inhabiting lucinid (late Jurassic) is described as Beauvoisina carinata gen. et sp. nov.; the new genus Cubatea is introduced for an Oligocene lucinid from Cuba. It is suggested that Caspiconcha, Paskentana, and hokkaidoconchids constitute the core of a seeprestricted fauna that inhabited seeps worldwide from (at least) late Jurassic to early Cretaceous time. These taxa are, at the family level, phylogenetically unrelated to the modern vent and seep fauna.

Special Publication; International audience; Dasycladales are unicellular green algae in existence since the Paleozoic era. Dasycladales discovered in the Cenozoic strata of the French sedimentary basins are noteworthy for the exceptional quality of their preservation. Although most fossil Dasycladales are known only in thin sections, the coatings of the Dasycladales in these basins, particularly of those in Lutetian beds, are easy to extract from sandy sediments and then are examined under the electron microscope. This method of investigation facilitates greatly the identification of the external and internal features of each species.

The geodynamic evolution of the Mediterranean area is characterized by the superimposition of convergence and extensional tectonic phases marked by the opening of sedimentary and oceanic basins onto a former thickened crust. The Calabro-Peloritan Arc (CPA) located astride the southern end of continental Italy and the northeastern Sicily corresponds to a segment of the former south-European active margin. This area, together with the Kabylian and Betico-Rifan massifs, was involved successively in shortening tectonics, associated to the subduction of the Tethyan oceanic lithosphere, and in extensional tectonics during the opening of the western Mediterranean basins. The CPA is a nappes-pile made of Alpine oceanic-derived units tectonically overlain by Hercynian metamorphics. This tectonic edifice was then transported onto the Apennine chain during the opening of the Tyrrhenian basin. The study presented here focused on the Aspromonte Massif which corresponds to the southern part of the CPA. The main purposes were to precise the geometry and the tectonometamorphic evolution of the units forming the uppermost part of the nappes-pile in order to better understand the conditions of the shortening to extension transition and the Oligocene Mediterranean kinematics. A multidisciplinary approach was used implying structural geology, microstructural and petrographic analysis of sampled rocks, thermobarometric estimates of the successive metamorphic phases and their dating by 40Ar/39Ar geochronology. Except for the evidences of a rather poorly constrained Hercynian evolution, the main results obtained show, a two steps Alpine evolution. The first step corresponds to a stacking phase; the second one corresponds to an extensional reworking of the entire nappes-pile. Metamorphic and geochronological data suggest that the piling was initiated in the middle of Eocene (~45 Ma) or earlier, while extension started probably in the lower Oligocene (since 33 Ma) and lasted until the middle Oligocene (27 Ma) without change in orientation. This second deformation phase leads to the progressive exhumation of the deepest units, partly controlled by a strong tectonic denudation. The kinematic directions of this reconstituted structural evolution, replaced in their initial position and orientation, before the CPA formation, imply a shortening direction in agreement with the bulk convergence direction between African and European plates at Eocene times. In the contrary, the age of the extensional phase indicates that the western Mediterranean tectonic thinning started probably at least in Lower Oligocene. In addition, its location and orientation suggest that it could be related to the opening of the North-Algerian basin, previously to the opening of the Liguro-Provencal basin and the associated SE-directed Tethyan slab retreat., L'évolution géodynamique des régions méditerranéennes est caractérisée par la succession de phases de convergence et de phases d'extension qui se marquent par l'ouverture de bassins sédimentaires et océaniques au niveau de zones initialement épaissies. L'Arc Calabro-Péloritain (ACP) situé à cheval sur la pointe sud de l'Italie continentale et sur la pointe nord-est de la Sicile, correspond à un fragment de l'ancienne marge active sud-européenne. Cette région à laquelle appartenaient également les massifs Kabyles, le Rif et les Cordillères Bétiques, a été impliquée successivement dans des épisodes de tectonique en raccourcissement, associés à la subduction de la lithosphère océanique téthysienne, et dans des épisodes de tectonique en extension pendant l'ouverture des bassins de la Méditerranée Occidentale. L'ACP est constitué d'une pile de nappes tectoniques impliquant des unités ophiolitifères alpines et des unités cristallophyliennes hercyniennes. Cet ensemble a été charrié sur la marge sédimentaire apulienne, et a été intégré dans l'édifice tectonique de la chaîne apenninique au cours de l'ouverture récente du bassin Tyrrhénien. Les travaux menés au cours de cette thèse se sont focalisés sur la partie sud de l'ACP, dans la région du Massif de l'Aspromonte. Ils visaient à préciser la géométrie et l'évolution tectonométamorphique des unités qui constituent la partie supérieure de l'édifice de nappes, afin de mieux comprendre les modalités de la transition convergence - extension, et la cinématique de l'évolution du domaine méditerranéen à l'Oligocène. Cette étude s'est appuyée sur une approche pluridisciplinaire impliquant la géologie structurale, l'étude pétrographique et microstructurale des roches échantillonnées, les estimations thermobarométriques des conditions des épisodes métamorphiques successifs et leur datation par la méthode 40Ar /39Ar.Les principaux résultats obtenus mettent en évidence, hormis les indices d'une évolution hercynienne assez mal contrainte, une évolution alpine impliquant deux étapes successives. La première correspond à l'empilement des unités tectoniques, la seconde à la reprise en extension de l'édifice de nappes. Les contraintes métamorphiques et géochronologiques suggèrent que l'empilement était déjà initié à l'Eocène moyen (~ 45 Ma), tandis que l'extension a probablement débuté à l'Oligocène inférieur (à partir de 33 Ma) et s'est prolongée au moins jusqu'à l'Oligocène moyen (27 Ma) avec les mêmes caractéristiques cinématiques. Cette seconde déformation entraîne l'exhumation des unités profondes, contrôlée en partie par une importante dénudation tectonique. Les directions cinématiques de cette évolution structurale replacées dans leur position et leur orientation initiales, avant la formation de l'ACP, impliquent une direction de raccourcissement en accord avec la direction de convergence Afrique-Eurasie reconstituée pour l'Eocène. En revanche l'âge de la phase d'extension indique que l'amincissement tectonique généralisé en Méditerranée Occidentale s'est initié au moins dès l'Oligocène inférieur. En outre la localisation et l'orientation de cette extension suggèrent qu'elle peut-être reliée à l'ouverture du Bassin Nord-Algérien, antérieurement à l'ouverture du Bassin Liguro-Provençal et au retrait de la zone de subduction vers le SE.

International audience; The Calabro-Peloritan belt constitutes the eastward termination of the southern segment of the Alpine Mediterranean belt. This orogenic system was built up during the convergence between the Eurasian and the African plates, roughly directed North-South since the Upper Cretaceous. It was subsequently fragmented during the opening of the Western Mediterranean basins since Oligocene times. The curved shape of the Calabro-Peloritan belt was acquired during the opening of the Tyrrhenian basin since Tortonian. The origin, kinematics and significance of the Calabro-Peloritan tectonic pile are still debated. Our data in the Aspromonte Massif of Southern Calabria reveal an Alpine history marked by two main superimposed kinematic regimes. (i) A first phase corresponds to the piling up of basement nappes with a top-to-the-SE vergence, i.e in a direction orthogonal to the belt trend and towards the Adriatic foreland. This external vergence is similar to what is observed in both Northeastern Sicily and Northern Calabria. In Sicily, the age of nappe piling is Alpine, as evidenced by pinched slices of Mesozoïc sediments. In the Aspromonte Massif, thrusting age is less constrained. Our data suggest remnants of late Hercynian structuration before the Alpine stacking. (ii) A second phase corresponds to the thinning of the continental crust, dated at around 30 Ma by both geochronological and stratigraphical data. This extension is mainly localized on two low-angle detachment contacts, with top-to-the-NE displacement. The lower one corresponds to the reworking of the former main nappe contact. The upper one is a large detachment fault cutting across the pile from upper sedimentary levels down to metamorphic basement. Extension of similar Alpine age and similar internal vergence has been already recognized in other parts of the Calabro-Peloritan Arc: in the basement nappes of Northeastern Sicily and in the ophiolitic units of Northern Calabria. Coming back to the original geometry and position of the Calabro-Peloritan belt, before its bending and the opening of the Liguro-Provençal and Tyrrhenian basins, we evidence a homogeneous Oligocene NE-SW extension all along the Calabro-Peloritan segment of the Alpine Mediterranean belt. This tectonometamorphic history is best explained within the framework of the continuous Tertiary westward dipping subduction of the Tethyan oceanic domain below the European active margin and the progressive eastward retreat of the Apennine trench since Oligocene times.

International audience; Euryhaline mollusks are adapted to large ranges of salinities in their life environment but are not reliable indicators of the marine or non-marine origin of dissolved ions. Many palaeogeographical controversies based on such ambiguous organisms are long lasting questions. This is the case for the some Rupelian deposits of the French Massif Central. In these deposits, the presence of a gastropod, Potamides lamarcki, has been considered to reflect various palaeoenvironments, from marine or marginal (lagoons or marine ingressions) to continental (brackish to saline lakes). As a marginal or marine fossil, it was used to reconstruct Oligocene seaways in the European Cenozoic rift system. The application of Sr isotope ratio of well preserved aragonitic fossils of P. lamarcki from Rupelian deposits in the Massif Central and in the Paris Basin is tested as a method of solving this problem. These data confirm the reliability of Sr isotopes in discriminating between euryhaline gastropods of marine origin in the Paris Basin and of continental origin in the French Massif Central. The Potamides lamarcki shells of the Paris Basin Rupelian gulf have 87Sr/86Sr ratios from 0.707744±18 to 0.707949±11, i.e. close to the Oligocene seawater range (0.70780–0.70820, McArthur et al., 2001). In contrast, the P. lamarcki shells collected in the Oligocene deposits of the French Massif Central have high 87Sr/86Sr ratios ranging from 0.713231±16 in the Limagne basin to 0.715205±13 in the Aurillac basin. These are very distinct from contemporaneous seawater and reflect the Sr isotopic compositions of local continental waters in these basins during the Rupelian. It is suggested that the Potamides lamarcki of the French Massif Central basins lived in intracontinental saline lakes rather than in lagoons with connection to seawater. Accordingly, the presence of P. lamarcki and of other euryhaline fossils cannot be taken as evidence of seawater influence in the distinct grabens of this region during the Oligocene and palaeogeographical reconstructions of the western part of the European Rift System should be reviewed.

International audience; We present the results of a paleomagnetic study of seven new volcanic sections (146 flows) from Kerguelen Archipelago. For two of these sections, preliminary (;40;Ar/;39;Ar) ages are reported to aid in the calibration of the paleomagnetic results. The primary contribution of this report, however, is a compilation of these new data with those already published in order to describe statistically the characteristics of the paleomagnetic field as recorded by the Kerguelen flood basalts. In total, 258 paleomagnetic directions sampled at 13 stratigraphic sections through the lava pile are available and span an approximately 5 Ma window: from 25 to 30 Ma. The composite section represents at least 11 polarity zones that are correlated to the reference geomagnetic polarity timescale. Our approach is to investigate the average normal and reversed polarity field directions over this 5 Ma window. We calculated a paleomagnetic pole found to be located at ;λ; = 85.5°N, = 189.3°E (A;95; = 2.3°, K = 16.5, N = 233). This pole is in close agreement with the coeval paleomagnetic poles obtained from different worldwide places when analyzed in the Indo-Atlantic hot spot reference frame. In the statistical analysis we tackle the specific question: Is the secular variation isotropic? This question is directly related to the occurrence of a longitudinal confinement of the virtual geomagnetic poles, which is still a matter of debate among paleomagnetists. By means of statistical tests we show that the paleomagnetic data from Kerguelen agree with an isotropic model for paleosecular variation. Finally, we present adjustments to Camps and Prévot's (1996) statistical model, developed for some Northern Hemisphere latitudes, to the Southern Hemisphere paleomagnetic data from Kerguelen.

International audience; Newly discovered fossil material of the enigmatic cetartiodactyl Bugtitherium grandincisivum from the upper Oligocene of the Bugti Member of the Chitarwata Formation in the Bugti Hills (Balochistan, Pakistan) is reported. These new specimens consist of two fragmentary muzzles (one preserving the first incisors and belonging to a juvenile) and a fragmentary right mandible with m3. The morphologies of the anterior dentition and m3 provided by these new specimens confirm the validity of the genus Bugtitherium and advocate probable anthracotheriid affinity for the genus rather than entelodontid or suoid affinities, but do not definitively close the debate about Bugtitherium?s familial affinities within Cetartiodactyla. Although still poorly documented, this large-sized anthracotheriid-like cetartiodactyl is a possible key form for understanding the early evolution of hippos, and, in turn, the ancestry of whales, because of both its morphological similarities with hippos and primitive Paleogene whales and its Tethysian distribution.

Closed pyrolyses were performed on the Boom Clay kerogen to simulate the weak thermal stress applied during the in situ CERBERUS heating experiment (80°C for 5 a). Two stronger thermal stresses, encompassing the range generally considered for the long-term disposal of high-activity nuclear waste (80°C for 1 ka and 120°C for 3 ka), were also simulated. Quantitative and qualitative studies were carried out on the products thus generated with a focus on the C12+ fraction, especially on its polar components. It thus appeared that the soluble C12+ fractions generated during these simulation experiments comprise a wide variety of polar O- and/or N-containing compounds, including carboxylic acids and phenols. The nature and/or the relative abundance of these polar compounds exhibit strong variations, with the extent of the thermal stress, reflecting the primary cracking of different types of structures with different thermal stability and the occurrence of secondary degradation reactions. These observations support the idea that the compounds, generated upon exposure of the Boom Clay kerogen to a low to moderate thermal stress, may affect the effectiveness of the geological barrier upon long-term storage of high-activity nuclear waste. © 2004 Elsevier Ltd. All rights reserved.

In southern New Caledonia, Late Oligocene granodiorite and adamellite are intruded into an ultramafic allochthon emplaced in the Late Eocene period. Previous studies of these granitoids proposed an origin associated with the melting of the underlying continental crust, but our new data show that these high-K to medium-K calc-alkaline granitoids display the geochemical and isotopic features of volcanic arc magmas uncontaminated by crust-derived melts. These magmas were probably generated in a post-Eocene and pre-Miocene subduction, the geophysical traces of which have been detected along the western coast of New Caledonia. Sr, Nd and Pb isotopic ratios indicate derivation from an almost isotopically homogeneous mantle wedge, but in contrast, some variation in trace element ratios uncorrelated to differentiation is indicative of source heterogeneity. Prominent heavy rare earth element (HREE) depletion of some of the younger granitoids may be the result of an equilibrium achieved with garnet-bearing subcrustal material (granulite) found as xenoliths, while a relative Nb, Ta and Hf enrichment, irrespective of crystal fractionation, may be related to either a modest contamination by previously underplated mafic material, heterogeneous hydration of the mantle wedge, or mixing with uplifted Nb-rich mantle. Post-obduction slab break-off can be proposed to have played a role in sublithospheric mantle mixing and the subsequent heterogeneity. The Late Oligocene subduction described here may be tentatively extended southward into northern New Zealand allochthons.

The family Thryonomyidae is known from the Eocene up to the present. Today, this group comprises just two closely related species, which are restricted to sub-Saharan Africa. However, various thryonomyids have been recorded in strata of Miocene age, when the group spread out of Africa eastward to southern Asia (Pakistan). A systematic revision and a cladistic analysis shows that 20 species can be referred to this family: Thryonomys swinderianus (Temninck), T. gregorianus (Thomas), Paraphiomys pigotti Andrews, P. occidentalis Lavocat, P. simonsi Wood, P. hopwoodi Lavocat, P. shipmani Denys et Jaeger, P. australis Mein, Pickford et Senut, P. roessneri Mein, Pickford et Senut, P. afarensis Geraads, Paraphiomys sp. nov. from Saudi Arabia López-Antoñanzas et Sen, P. renelavocati sp. nov., Neosciuromys africanus Stromer, Apodecter stromeri Hopwood, Paraulacodus indicus Hinton, Paraulacodus johanesi Jaeger, Michaux et Sabatier, Gaudeamus aegyptius Wood, Epiphiomys coryndoni Lavocat, Kochalia geespei (de Bruijn et Hussain), Paraphiomys sp. nov. from Saudi Arabia, and Paraphiomys orangeus Mein et Pickford. The unresolved basal position of Sacaresia moyaeponsi with respect to Metaphiomys schaubi and the clade comprising the above-cited species, suggest that this taxon should not be allocated to the family Thryonomyidae. A phylogenetic definition of the family Thryonomyidae is proposed as an outcome of the phylogenetic analysis: Epiphiomys corindoni, Thryonomys swinderianus, their most recent common ancestor and all its descendants (node-based taxon)., The research of R. L. is supported by a grant from the Caixa Fundation in collaboration with the French government.