Histoire des premiers peuplements béringiens : étude archéozoologique et taphonomique de la faune des Grottes du Poisson-Bleu (Territoire du Yukon, Canada)

Beringia, a vast landscape stretching from eastern Siberia to the Yukon Territory, is thought to be the initial entry point of humans into North and South America. At the end of the Pleistocene, this unglaciated region constituted a refugium for the first prehistoric populations dispersing out of Asia. According to genetic and palaeogenetic data, Beringia was occupied during the Last Glacial Maximum (19 000-23 000 cal BP, calibrated years before present) by a human population that remained genetically isolated for about 8000 to 9000 years, leading to the divergence of the Native American lineage that would eventually disperse south of the ice-sheets into North and South America. The « Beringian standstill hypothesis » is not well supported in the archaeological record, however: in eastern Siberia, the oldest archaeological site is dated to 32 000 cal BP while in Alaska and the Yukon, evidence for a human presence doesn’t exceed 14 000 cal BP. Excavated in the 70s-80s, the Bluefish Caves site (Yukon) yielded stone tools and bone remains thought to have been culturally modified, buried in a Pleistocene loess deposit; the discovery encouraged archaeologists J. Cinq-Mars and R. Morlan to propose that humans occupied the caves sporadically between about 11 000 and 30 000 cal BP. The anthropogenic nature of the bone samples submitted for radiocarbon analysis and the stratigraphic integrity of the site didn’t convince the scientific community, however. The current dissertation proposes a rigorous archaeozoological and taphonomic analysis of the mammal bone assemblages of Caves I and II in order to identify the agents responsible for the accumulation and modification of the bone material. The results show several cut marks on bone specimens belonging to horse, caribou, wapiti and possibly bison and Dall sheep, while mammoth skeletal remains may have been collected for bone industry. New radiocarbon dates obtained by an Oxford laboratory (Oxford Radiocarbon Accelerator Unit) on bone bearing indisputable evidence of cultural modification allow the precise dating of the human occupation at the site. The AMS dates suggest that the Bluefish Caves were occupied sporadically between 12 000 to 24 000 cal BP, i.e., during and after the Last Glacial Maximum. The site, therefore, offers archaeological support for the Beringian standstill hypothesis. The taphonomic history of the Bluefish Caves, as well as other Beringian karstic sites, shows use of the caves by various carnivores and short-term human occupations for hunting activities. Moreover, cultural modifications on horse bone from Caves I and II enhance the debate surrounding the megafaunal extinctions at the end of the Pleistocene (ca. 14 000 cal BP). The site underlines the incompleteness of the archaeological record and invites us to expand research efforts in Beringia if we are to understand the prehistory of the first people of the Americas.

Keyphrases: Taphonomie, Dispersions humaines, Subsistance, Beringia, North America, Pleistocene, Last Glacial Maximum, First peopling, Archaeozoology, Taphonomy, Human dispersals, Subsistence, Megafauna