0000000001230698
AUTHOR
Benjamin Bourel
Middle Jurassic tracks of sauropod dinosaurs in a deep karst cave in France.
14 pages; International audience; Although the deep galleries of natural underground cavities are difficult to access and are sometimes dangerous, they have the potential to preserve trace fossils. Here, we report on the first occurrence of sauropod dinosaur tracks inside a karstic cave. Three trackways are preserved on the roof of the Castelbouc cave 500 m under the surface of the Causse Méjean plateau, southern France. The tracks are Bathonian in age (ca. 168–166 Ma), a crucial but still poorly known time interval in sauropod evolution. The three trackways yield sauropod tracks that are up to 1.25 m long and are therefore amongst the largest known dinosaur footprints worldwide. The trackm…
Lowermost Jurassic dinosaur ecosystem from the Bleymard Strait (southern France): sedimentology, mineralogy, palaeobotany and palaeoichnology of the Dolomitic Formation.
AbstractWe report the first Hettangian theropod tracksite (~200 Ma) yielding a rich accumulation of plant remains from the Bleymard Strait (southern France). It constitutes an excellent opportunity to reconstruct lowermost Jurassic ecosystems hosting dinosaurs and which are still poorly documented in this area. Two morphotypes of tridactyl tracks are distinguished. They share similarities with Grallator and Kayentapus. Plant-bearing beds yield abundant leafy axes (Pagiophyllum peregrinum), male cones (Classostrobus sp.), wood (Brachyoxylon sp.) and pollen of conifers (Classopollis classoides). Sedimentological, petrological and mineralogical analyses demonstrated that, in the Dolomitic Form…
Vegetation dynamics of Kisima Ngeda freshwater spring reflect hydrological changes in northern Tanzania over the past 1200 years: implications for paleoenvironmental reconstructions at paleoanthropological sites.
13 pages; International audience; Kisima Ngeda (KN), a spring on the northern margin of saline Lake Eyasi, Tanzania, sustains an Acacia-Hyphaene palm woodland and Typha swamps, while the surrounding vegetation is semi-desert. To study the vegetation changes associated with this spring, which represents a plausible modern analog for the fossil springs documented in the nearby paleoanthropological and archaeological sites of Olduvai Gorge, we analyzed the pollen content of a 43 cm-long sediment core that documents vegetation changes since the last ~1200 years (from cal yrs. C.E. 841 to 2011). Our results show that (1) Hyphaene palms, which require meso-halophytic soil conditions were most abu…
Fossiliferous Holocene tufa of Mende (Lozère, southern France): implication for the Atlantic vegetation of the Causses Basin
International audience; Tufas bearing plant macroremains are uncommon in the Causses Basin (southern France). Here, we report anew fossiliferous tufa deposits at Mende, in Lozère. This palaeontological site is the first Quaternary tufa from thenorthern part of the Causses Basin that yields such an abundance of plant macroremains. The radiocarbon dating showsthat these Holocene deposits are related to the Atlantic period. Geomorphology and mineralogy show that theplant-bearing deposit is a calcareous tufa only composed by calcite, deposited near to an outlet of cool water, linked tothe karstic hydrological system of the Causse de Mende. The flora exposed in this article is dominated by angio…
Des empreintes de dinosaures dans les karsts des Grands Causses : grottes de Malaval et Castelbouc IV.
National audience; La préservation de traces de dinosaures dans les grottes des Grands Causses fait de ces karsts des sites d'intérêt patrimonial et scientifique majeur. Pourtant, ces lieux remarquables n’avaient jusqu’ici jamais fait l’objet d'une étude paléontologique poussée. Les premiers travaux scientifiques viennent de révéler un patrimoine ichnologique insoupçonné dans les grottes de Lozère : la grotte de Malaval et la grotte de Castelbouc IV. Des empreintes de dinosaures théropodes d’âge Jurassique inférieur ainsi que des pistes de grands dinosaures sauropodes d’âge Jurassique moyen ont respectivement été découvertes dans ces deux cavités.
Les empreintes de dinosaures de Mende : de la fouille à l'étude paléontologique.
International audience; Disparus il y a près de 65 millions d’années, les dinosaures fascinent petits et grands, amateurs et scientifiques. Cependant, ces « terribles lézards » suscitent encore aujourd’hui beaucoup d’interrogations. C’est notamment le cas des dinosaures qui peuplaient l’Aveyron et la Lozère il y a 200 millions d’années, au Jurassique inférieur. Les ossements de dinosaures étant extrêmement rares dans les roches de cette époque, l’étude de leurs empreintes est primordiale. La région des causses est d’ailleurs un des plus importants secteurs d’Europe pour l’étude des traces de pas. C’est dans ce contexte qu’une nouvelle dalle à empreintes a récemment été découverte à Mende, e…