12 research outputs found
Histoire des premiers peuplements béringiens : étude archéozoologique et taphonomique de la faune des Grottes du Poisson-Bleu (Territoire du Yukon, Canada)
La BĂ©ringie, un vaste territoire qui sâĂ©tend de la SibĂ©rie orientale au Territoire du Yukon, est perçue comme le point dâentrĂ©e des populations humaines en AmĂ©rique. A la fin du PlĂ©istocĂšne, ce territoire dĂ©glacĂ© aurait constituĂ© un refuge aux premiĂšres populations prĂ©historiques se dispersant hors dâAsie. Selon les donnĂ©es gĂ©nĂ©tiques et palĂ©o-gĂ©nĂ©tiques, la BĂ©ringie fut occupĂ©e au cours du Dernier Maximum Glaciaire (19 000-23 000 cal BP, annĂ©es calibrĂ©es Before Present) par une population humaine qui demeura gĂ©nĂ©tiquement isolĂ©e durant prĂšs de 8000 Ă 9000 ans, donnant ainsi naissance Ă la lignĂ©e des Natifs AmĂ©ricains qui allaient se disperser, plus tard, au sud des masses glaciaires nordamĂ©ricaines et jusquâen AmĂ©rique du Sud. Cette « Beringian standstill hypothesis », toutefois, ne trouva aucun soutien dans le registre archĂ©ologique : en SibĂ©rie orientale, le plus ancien site est datĂ© Ă 32 000 cal BP, tandis quâen Alaska et au Yukon, la prĂ©sence humaine ne remonte pas au-delĂ de 14 000 cal BP. Dans les annĂ©es 70-80âs, le site des Grottes du Poisson-Bleu (Yukon) livra des outils en pierre et des ossements supposĂ©s modifiĂ©s par les humains, enfouis dans un dĂ©pĂŽt loessique plĂ©istocĂšne ; les dĂ©couvertes encouragĂšrent les archĂ©ologues J. Cinq-Mars et R. Morlan Ă Ă©voquer lâhypothĂšse dâune occupation humaine sporadique dans le nord du Yukon entre 11 000 et 30 000 cal BP environ. La nature anthropogĂ©nique des Ă©chantillons osseux soumis aux datations radiocarbones ainsi que lâintĂ©gritĂ© de la stratigraphie furent toutefois remises en question par une majoritĂ© dâarchĂ©ologues.
La prĂ©sente dissertation propose une analyse archĂ©ozoologique et taphonomique rigoureuse et systĂ©matique des assemblages fauniques de mammifĂšres des Grottes I et II dans le but dâapprĂ©hender les facteurs responsables de lâaccumulation et de la modification du matĂ©riel osseux. De nouvelles datations radiocarbones effectuĂ©es par le laboratoire Oxford Radiocarbon Accelerator Unit sur des ossements portant des traces indĂ©niablement culturelles permettent une datation prĂ©cise de lâoccupation humaine du site. Les rĂ©sultats illustrent plusieurs traces de dĂ©coupe sur des os de cheval, caribou, wapiti et possiblement bison et mouflon, tandis que des ossements de mammouth pourraient avoir Ă©tĂ© collectĂ©s pour lâindustrie osseuse. Les nouvelles datations AMS suggĂšrent que les Grottes du Poisson-Bleu Ă©taient occupĂ©es de façon sporadique entre 12 000 et 24 000 cal BP, soit pendant et aprĂšs le Dernier Maximum Glaciaire. Le site offre ainsi un soutien archĂ©ologique Ă lâhypothĂšse de lâisolation gĂ©nĂ©tique des populations bĂ©ringiennes Ă lâorigine des premiĂšres dispersions en AmĂ©rique. Lâhistoire taphonomique des Grottes du Poisson-Bleu rejoint celle des sites karstiques bĂ©ringiens qui illustrent des occupations interspĂ©cifiques alternĂ©es entre carnivores et des frĂ©quentations humaines de courte durĂ©e pour des activitĂ©s de chasse. En outre, les altĂ©rations anthropiques sur des os de cheval des Grottes I et II ravivent le dĂ©bat sur les extinctions de la mĂ©gafaune Ă la fin du PlĂ©istocĂšne (ca. 14 000 cal BP). Le site souligne lâincomplĂ©tude du registre archĂ©ologique et invite Ă multiplier les efforts de recherche en BĂ©ringie si lâon veut ĂȘtre Ă mĂȘme de comprendre la prĂ©histoire du peuplement des AmĂ©riques.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 doesnât 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 didnât 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
Beringia and the peopling of the Western Hemisphere
Did Beringian environments represent an ecological barrier to humans until less than 15 000 years ago or was access to the Americas controlled by the spatialâtemporal distribution of North American ice sheets? Beringian environments varied with respect to climate and biota, especially in the two major areas of exposed continental shelf. The East Siberian Arctic Shelf (âGreat Arctic Plainâ (GAP)) supported a dry steppe-tundra biome inhabited by a diverse large-mammal community, while the southern Bering-Chukchi Platform (âBering Land Bridgeâ (BLB)) supported mesic tundra and probably a lower large-mammal biomass. A human population with west Eurasian roots occupied the GAP before the Last Glacial Maximum (LGM) and may have accessed mid-latitude North America via an interior ice-free corridor. Re-opening of the corridor less than 14 000 years ago indicates that the primary ancestors of living First Peoples, who already had spread widely in the Americas at this time, probably dispersed from the NW Pacific coast. A genetic âarctic signalâ in non-arctic First Peoples suggests that their parent population inhabited the GAP during the LGM, before their split from the former. We infer a shift from GAP terrestrial to a subarctic maritime economy on the southern BLB coast before dispersal in the Americas from the NW Pacific coast
Earliest Human Presence in North America Dated to the Last Glacial Maximum: New Radiocarbon Dates from Bluefish Caves, Canada
The timing of the first entry of humans into North America is still hotly debated within the scientific community. Excavations conducted at Bluefish Caves (Yukon Territory) from 1977 to 1987 yielded a series of radiocarbon dates that led archaeologists to propose that the initial dispersal of human groups into Eastern Beringia (Alaska and the Yukon Territory) occurred during the Last Glacial Maximum (LGM). This hypothesis proved highly controversial in the absence of other sites of similar age and concerns about the stratigraphy and anthropogenic signature of the bone assemblages that yielded the dates. The weight of the available archaeological evidence suggests that the first peopling of North America occurred ca. 14,000 cal BP (calibrated years Before Present), i.e., well after the LGM. Here, we report new AMS radiocarbon dates obtained on cut-marked bone samples identified during a comprehensive taphonomic analysis of the Bluefish Caves fauna. Our results demonstrate that humans occupied the site as early as 24,000 cal BP (19,650 ± 130 14C BP). In addition to proving that Bluefish Caves is the oldest known archaeological site in North America, the results offer archaeological support for the âBeringian standstill hypothesisâ, which proposes that a genetically isolated human population persisted in Beringia during the LGM and dispersed from there to North and South America during the post-LGM period
Earliest Human Presence in North America Dated to the Last Glacial Maximum: New Radiocarbon Dates from Bluefish Caves, Canada
The timing of the first entry of humans into North America is still hotly debated within the scientific community. Excavations conducted at Bluefish Caves (Yukon Territory) from 1977 to 1987 yielded a series of radiocarbon dates that led archaeologists to propose that the initial dispersal of human groups into Eastern Beringia (Alaska and the Yukon Territory) occurred during the Last Glacial Maximum (LGM). This hypothesis proved highly controversial in the absence of other sites of similar age and concerns about the stratigraphy and anthropogenic signature of the bone assemblages that yielded the dates. The weight of the available archaeological evidence suggests that the first peopling of North America occurred ca. 14,000 cal BP (calibrated years Before Present), i.e., well after the LGM. Here, we report new AMS radiocarbon dates obtained on cut-marked bone samples identified during a comprehensive taphonomic analysis of the Bluefish Caves fauna. Our results demonstrate that humans occupied the site as early as 24,000 cal BP (19,650 ± 130 14C BP). In addition to proving that Bluefish Caves is the oldest known archaeological site in North America, the results offer archaeological support for the âBeringian standstill hypothesisâ, which proposes that a genetically isolated human population persisted in Beringia during the LGM and dispersed from there to North and South America during the post-LGM period
Cut marks on a caribou coxal bone from Cave II.
<p>The specimen (# I5.6.5) is dated to 18,570 ± 110 <sup>14</sup>C BP (OxA-33777) and shows straight and parallel marks resulting from filleting activity.</p
Previous radiocarbon dates obtained on bone from Bluefish Caves I (MgVo-1) and II (MgVo-2).
<p>Previous radiocarbon dates obtained on bone from Bluefish Caves I (MgVo-1) and II (MgVo-2).</p
Cut marks on a horse mandible from Cave II.
<p>The specimen (# J7.8.17) is dated to 19,650 ± 130 <sup>14</sup>C BP (OxA-33778). The bone surface is a bit weathered and altered by root etching but the cut marks are well preserved; they are located on the medial side, under the third and second molars, and are associated with the removal of the tongue using a stone tool [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref048" target="_blank">48</a>].</p
New radiocarbon determinations obtained on bone from Bluefish Caves I and II.
<p>The red dot on the map indicates the location of the site. Conventional radiocarbon ages are expressed in <sup>14</sup>C BP [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref070" target="_blank">70</a>], values are ± one standard error [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref071" target="_blank">71</a>]. Calibrations (cal BP) were made using OxCal 4.2 [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref067" target="_blank">67</a>] and the INTCAL113 calibration curve [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref068" target="_blank">68</a>]. âUsedâ represents the amount of bone powder pretreated in milligrams. âYieldâ represents the weight of collagen or ultrafiltered collagen in milligrams. â%Yieldâ is the percent yield of extracted collagen as a function of the starting weight of the bone analyzed. â%Câ is the carbon present in the combusted collagen and averages 40 ± 2% in the ORAU. Stable isotope ratios are expressed in â° relative to vPDB [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref072" target="_blank">72</a>] with a mass spectrometric precision of ± 0.2 â° for C and ± 0.3 â° for N. âCNâ is the atomic ratio of C to N and is acceptable if it ranges between 2.9â3.5. <sup>a</sup>Denote duplicate measurements from the start of the pretreatment chemistry. <sup>b</sup>Specimen also identified in previous article [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0169486#pone.0169486.ref039" target="_blank">39</a>].</p