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RÉSUMÉ Un site paléontologique du Sud-Ouest du Bassin parisien est décrit: l'ancienne falunière du Grand Morier. Il se situe à l'ouest de la ville de Langeais et au sud du hameau de Pont-Boutard (Indre-et-Loire, France). Le contexte géologique du Grand Morier est complexe. Toutes les formations sédimentaires cénozoïques locales sont représentées sur le site: les formations continentales étagées depuis le Paléogène moyen jusqu'au Miocène, les faluns marins du Miocène et les formations continentales de la fin du Néogène. Les phénomènes de tectonique locale (phases pyrénéenne et alpine) ont contraint et canalisé la sédimentation cénozoïque dans une structure en graben. De nombreux fossiles de vertébrés cénozoïques ont été trouvés dans le site paléontologique du Grand Morier. La consultation de 450 fossiles de vertébrés conservés dans différentes collections a permis de réaliser une liste faunique composée de 102 taxons. Les données géologiques et taphonomiques ont permis de reconstituer des assemblages de fossiles de même âge et de même état de conservation. Six ensembles biostratigraphiques bien distincts ressortent: deux faunes continentales en place de l'Éocène (MP12 à MP20) et Oligocène-Agénien supérieur (MP24 à MN2), une faune marine en place — ou faiblement remaniée — dans les faluns miocènes (Burdigalien supérieur à Tortonien) et trois faunes remaniées (Crétacé supérieur au Miocène) dans les faluns miocènes. Ces assemblages de fossiles de vertébrés recadrent et précisent la stratigraphie du Cénozoïque local. ABSTRACT The paleontological site of Le Grand Morier (Pont-Boutard, Indre-et-Loire, France): geological context and vertebrate biostratigraphy of the Cenozoic formations. A paleontological site of the Paris Basin is described here: Le Grand Morier quarry. This site is located West of the Langeais city and South of the hamlet of Pont-Boutard (Indre-et-Loire, France). The geological context of Le Grand Morier is complex. The site comprises all local late Cenozoic sedimentary formations cropping out locally: the Paleogene to lower Orleanian continental formations, the Miocene marine shelly sands and the Upper Neogene continental formations. Local tectonic phenomena (Pyrenean and Alpine phases) created a graben structure, which has focused most of the Cenozoic sedimentation. Many fossils of Cenozoic vertebrates have been found in the paleontological site of Le Grand Morier. For the purpose of this study, 450 fossils of vertebrates (102 taxa) have been studied in various paleontological collections. The geological and taphonomic contexts enabled the recognition of fossil clusters based on their hypothesized age and preservation state. The paleontological study reveals six distinct groups: two in situ continental faunas Eocene (MP12 to MP20) and Oligocene-Early Miocene (MP24 to MN2) in age, an in situ or slightly reworked Miocene marine fauna (upper Burdigalian to Tortonian) and three clusters of reworked fossils (upper Cretaceous to Miocene) in the Miocene shelly sands. These vertebrate fossils clusters improve the resolution of the Cenozoic stratigraphic framework of the area. ABRIDGED ENGLISH VERSION The paleontological site of Le Grand Morier is located in the heart of the Ligerian Basin, 40 kilometers West from the city of Tours (Temey 1996). This fossiliferous site corresponds to an old quarry where the Miocene shelly sand was exploited (Fig. 1). The most important geological and paleontological studies of Le Grand Morier are those of Lecointre (1930, 1947), Alcaydé (1975) and Alcaydé et al. (1976) for the geological surveys (geological mapping, stratigraphy and structural studies) and of Buge (1948) and Ginsburg (2001) for their work on the fossils (bryozoans and Miocene land mammals respectively). This article presents original data on the geological context and the stratigraphy of the Cenozoic sedimentary series of Le Grand Morier site (Fig. 2). Cenozoic outcrops are numerous and diversified in Anjou-Touraine (Lecointre 1947). Looking at the regional geological maps is enough to realize that the Cretaceous is covered by continental Paleogene formations and marine Neogene formations (Alcaydé & Rasplus 1971; Alcaydé 1975). To our knowledge, Le Grand Morier is the only known site in Anjou-Touraine with exposures of all Cenozoic formations (albeit small outcrops for some of them), from the Paleocene-Eocene “perrons de Touraine” to the Late Miocene to Pliocene gravel sands (Fig. 4). This site is exceptional because vertebrate fossils have been found in each outcropping formation. In addition, this paleontological site is located into a local tectonic structure: the Pont-Boutard graben (Fig. 3). Integrating the structural and stratigraphic clearly shows that the Cenozoic sedimentation is a syntectonic sedimentation constrained and channeled by the structurally-active Pont-Boutard graben. Specifically, the establishment of the continental formations (fluviatile and lacustrine deposits) during the middle Cenozoic (Eocene to earliest Miocene) was made possible by the formation of a basin controlled by two faults activated by the Pyrenan orogeny (Fig. 2). The Alpine orogeny (Miocene) accentuated the deepening of the Pont-Boutard graben, safeguarding a major part of the Cenozoic sedimentary series (Paleocene to Miocene), but also redirecting the prograding marine sediments from the basin of Savigné-sur-Lathan/Noyant-sous-le-Lude towards the basin of Paulmy in Southern Touraine. By compiling all the geological (stratigraphy, sedimentology, and taphonomy) and paleontological data, it is possible to consider six successive assemblages of vertebrate faunas (102 taxa), reworked or not. The assemblage no. 1 contains one tooth of Plagiolophus cf. annectens (Owen, 1847) (Fig. 7); found in the Middle to Late Eocene lacustrine green clay (MP12 to MP20). The assemblage no. 2 contains four land mammals either Oligocene (Ronzotherium cf. romani: MP24–29) or Early Miocene in age (Agenian-Aquitanian): Phoberocyon hispanicus Ginsburg & Morales, 1998, Protaceratherium minutum (Cuvier, 1822–1824), Paratapirus intermedius (Filhol, 1885) (Fig. 7). The fossils have been found in the lacustrine limestone underlying the Miocene marine shelly sand. It is an important new input for the Cenozoic biostratigraphy of the Anjou-Touraine area. This lacustrine limestone known as “le calcaire lacustre de Touraine”, has always been dated as Late Eocene to Oligocene (Alcaydé 1975; Yvard 1976). The presence in our site of land mammals similar to the fossils observed in the Early Miocene locality of Selles-sur-Cher (Loir-et-Cher, France, Ginsburg & Hugueney 1980; Antoine et al. 2000) together with a typical Oligocene rhinocerotid enables us to consider that geological formation may range from the late early Oligocene to the Agenian, MP24 to MN2 (Bruijn et al. 1992; Aguilar et al. 1997). The assemblage no. 3 is exclusively composed of well-known Miocene marine vertebrates (fishes and mammals): Isurus desori, Cosmopolitodus hastalis, Otodus megalodon, Carcharias (Odontaspis) acutissima ou Carcharias (Odontaspis) cuspidata, Carcharias sp., Carcharhinus priscus, Galeocerdo aduncus, Negaprion kraussi, Hemipristis serra, Notorhynchus primigenius, Dasyatis sp., Myliobatidae indet., Aetobatus arcuatus, Pristis aquitanicus, Sparus cinctus, Sparus aurata, Diplodus jomnitanus, Sphyraena olisiponensis, Labrodon pavimentatum, Tetrodon lecointrae, Trigonodon jugleri, Metaxytherium sp., Cetacea indet. and Orycterocetus crocodilinus. Numerous publications have already presented this typical faunal list of the Ligerian basin (Mornand 1978; Ginsburg & Mornand 1986) the age of which ranges covers most of the Miocene epoch: from the late Burdigalian to the Tortonian (Bouchet 2009). The assemblage no. 4 is composed of rare late Cretaceous fossils (Squalicorax sp., Cretolamna sp., Ptychodus sp.) reworked in the Miocene shelly sand. These fossils are too damaged for providing more detailed information. The assemblage no. 5 contains a vertebrate fauna from the early Orleanian (MN3): Ptychogaster sp., Testudo sp., Trionyx sp., Diplocynodon sp., Lagopsis sp., Eucricetodon infralactorensis, Steneofiber depereti, Amphicyon (Megamphicyon) lathanicus, Cynelos helbingi, Cynelos schlosseri, Haplocyonoides mordax, Ballusia hareni, Phoberocyon aurelianensis, Phoberocyon dehmi, Plithocyon bruneti, Hemicyon gargan, Martes laevidens, Palaeogale hyaenoides, Plesiogale angustifrons, Pseudaelurus turnauensis, Anchitherium aurelianense, Protaceratherium minutum, Diaceratherium aurelianense (Fig. 6), Aureliachoerus aurelianensis, Xenohyus venitor, Brachyodus onoideus, Brachyodus intermedius, Procervulus dichotomus, Heterocemas sp., Ligeromeryx praestans and Andegameryx andegaviensis. These fossils have undergone a very low reworking as proven by their good state of preservation and the presence of a fluvial sand lens from the early Orleanian in the eastern part of the paleontological site (Fig. 5). A larger set of late Orleanian (MN5) fossils composes the assemblage no. 6: Chelydropsis sp., Ptychogaster sp., Testudo promarginata, Testudo sp., Trionyx sp., Lacertidae indet., Boidae indet., Colubridae indet., Viperidae indet., Diplocynodon styriacus, Diplocynodon sp., Tomistoma cf. lusitanica, Gavialis sp., Incertae sedis, Proscapanus sansaniensis, Lagopsis sp., Steneofiber depereti, Anchitheriomys wiedemanni, Pliopithecus piveteaui, Hyainailouros sulzeri, Amphicyon giganteus, Agnotherium grivensis, Pseudocyon sansaniensis, Pseudarctos bavaricus, Hemicyon sansaniensis, Trocharion albanense, Protictitherium gaillardia, Pseudaelurus romievensis, Pseudaelurus lorteti, Pseudaelurus turnauensis, Prodeinotherium bavaricum, Gomphotherium angustidens, Zygolophodon turicensis, Anchitherium aurelianense, Anisodon grande, Brachypotherium brachypus, Plesiaceratherium lumiarense, Prosantorhinus germanicus, Prosantorhinus douvillei, Lartetotherium sansaniensis, Aureliachoerus aurelianensis, Bunolistrio

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Le site paléontologique du Grand Morier (Pont-Boutard, Indre-et-Loire, France): contexte géologique et détail biostratigraphique des formations cénozoïques à partir des assemblages de vertébrés fossiles