The Late Pleistocene Dispersal of
Modern Humans in the Americas
Ted Goebel,1* Michael R. Waters,2 Dennis H. O’Rourke3
Science March 13 2008
A "few" comments:
“…Current genetic evidence implies dispersal from a single Siberian population toward the Bering Land Bridge no earlier than about 30,000 years ago (and possibly after 22,000 years ago), then migration from Beringia to the Americas sometime after 16,500 years ago. The archaeological records of Siberia and Beringia generally support these findings, as do archaeological sites in North and South America dating to as early as 15,000 years ago. If this is the time of colonization, geological data from western Canada suggest that humans dispersed along the recently deglaciated Pacific coastline…”
A big “if” in the above statement (last sentence). And note there is no reference to “earliest” colonization.
"...Based on the modern and ancient DNA records, then, Asia was the homeland of the first Americans, not Europe, lending no support to the recently proposed “Solutrean hypothesis,” that the progenitors of Clovis were derived from an Upper Paleolithic population on the Iberian Peninsula (15, 16)..."
I know Waters has always been at odds with the “Solutrean hypothesis”, but, from what I’ve gathered from his research, he’s not against the idea of a pre-LGM migration from Asia:
“…Current Projects…
Topper site, South Carolina
The Topper site is a proposed Pre-Clovis locality that is being excavated under the direction of Dr. Al Goodyear (South Carolina Institute of Archaeology and Anthropology). Michael Waters in conjunction with Steve Forman (University of Illinois, Chicago), Tom Stafford (Stafford Research Laboratories), and John Foss (University of Tennessee) have been conducting geoarchaeological investigations of the site since 1999. This geoarchaeological fieldwork was completed at the Topper site in 2004. A final report on the geology of the site is nearing completion. While the geological context and age of the sediments that contain the reported Pre-Clovis artifacts are secure, questions remain about the origin of the reported artifacts. The Topper assemblage may be the result of human manufacture or may also be the result of natural thermal spalling. To investigate this question, the Center’s Digital Imaging Lab conducted a preliminary microscopic use-wear study on several specimens provided by Goodyear in 2003 from the pre-Clovis sediments. The results are equivocal. Chert from this area weathers rather quickly and the surface of these pieces is badly degraded. It appears as a thick white patina making such a study difficult at best. For example, the true degree of edge rounding is difficult to ascertain because the surface degradation affects the appearance of edges. In addition, linear indicators and polish that are visible lie on the weathered surface and one would suppose that ancient people would have used these pieces for tools before such weathering occurred.
http://www.centerfirstamericans.org/new/topper_figure_1.jpg http://www.centerfirstamericans.org/new/topper_figure_2.jpg http://www.centerfirstamericans.org/new/topper_figure_3.jpg …”
Here are a few artifacts from the 17,000-19,000 year old (calibrated) strata at Topper:
http://www.centerfirstamericans.org/photos/albums/userpics/10001/p~1.jpg http://www.allendale-expedition.net/museum/topchop.jpg http://www.phpbb88.com/nohandaxesinus/viewtopic.php?mforum=nohandaxesinus&t=65&postdays=0&postorder=asc&start=3&mforum=nohandaxesinus http://www.phpbb88.com/nohandaxesinus/viewtopic.php?mforum=nohandaxesinus&t=65&postdays=0&postorder=asc&start=4&mforum=nohandaxesinus “…We were able to confirm that the Hueyatlaco Ash did indeed overlie what was reported to be the unifacial artifact-bearing deposits (Bed I)…”
http://www.centerfirstamericans.org/research.php#current_projects Back to the paper:
“…New analyses of haplogroup subclades help to resolve when modern humans subsequently spread from Beringia to the rest of the Americas. Three subclades of mtDNA subhaplogroup C1 are widely distributed among North, Central, and South Americans but absent in Asian populations, which suggests that they evolved after the central Asian–Native American split, as the first Americans were dispersing from Beringia (27). The estimated date of coalescence for these subclades is 16.6 to 11.2 ka, which suggests that the colonization of the Americas south of the continental ice sheets may have occurred sometime during the late-glacial period, thousands of years after the initial splitting of Asian and Native American lineages….”
A second opinion:
“…The phylogenies of haplogroups A2, B2, C1, and D1 reveal a large number of sub-haplogroups but suggest that the ancestral Beringian population(s) contributed only six (successful) founder haplotypes to these haplogroups. The derived clades are overall starlike with coalescence times ranging from 18,000 to 21,000 years (with one exception) using the conventional calibration…”
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0001764 “…As yet, no unequivocal traces that the early people of Yana RHS explored farther east onto the Bering Land Bridge and crossed into Alaska and northwest Canada have been found, but hints of an early human presence may include the 28-ka mammoth-bone core and flake recovered from Bluefish Caves (Yukon Territory) and even older bone materials from along the nearby Old Crow River (38)…”
Good to see Jacques get some more press!
“…A small number of undated fluted points similar to Clovis occur in Alaska (39), but their relation to Clovis points found south of the continental ice sheets is unknown and may represent the backward flow of technologies (or people) from mid-latitude North America to Beringia at the very end of the Pleistocene (22, 39)…”
Clovis headed north?
“…Since 40 ka, the Cordilleran and Laurentide ice sheets covered much of Canada, but during warmer periods they retreated sufficiently to create ice-free corridors along the Pacific coast and Plains east of the Canadian Rockies. These corridors were the conduits through which the first humans spread from Beringia to the Americas.When humans arrived in arctic Siberia at Yana RHS 32 ka, contracted ice sheets left wide-open corridors through which humans could have passed, but by 24 ka the ice sheets had grown sufficiently to clog both passageways…”
Pre-LGM migrations south?
“…The archaeological records of both corridors are still inadequate for addressing questions about the initial peopling of the Americas; however, the presence of human remains dating to 13.1 to 13 ka at Arlington Springs, on Santa Rosa Island off the coast of California, indicates that the first Americans used watercraft (46)…”
I’m sure some will want to comment on this. I'm not sure how 13.1 to 13 ka qualifies as first?
“…With recently excavated Clovis assemblages, especially from the southeastern United States and Texas, we know unequivocally that Clovis is characterized by not only bifacial technology but also distinctive Upper Paleolithic blade technology (Fig. 2) (15, 48)…”
“…In the southeastern United States and Texas, however, enormous scatters of Clovis artifacts have been found that possibly represent quarry habitation sites habitually used by Clovis people, from which they did not range great distances…”
Gault (Collins) and Buttermilk Creek (Waters) are absolutely loaded with Clovis artifacts. I’ve heard figures as high as 60% of all known Clovis artifacts.
“…Even earlier evidence of humans in Wisconsin is suggested by what appear to be cut and pry marks on the lower limb bones of a mammoth recovered from Mud Lake. These bones date to 16 ka, but stone tools are absent (61)…”
Inching back from 15,000 years ago…
“…Three other sites—Meadowcroft Rockshelter (Pennsylvania), Page-Ladson (Florida), and Paisley Cave (Oregon)—may provide additional evidence of humans in North America by about 14.6 ka. At Meadowcroft Rockshelter, artifacts occur in sediments that may be as old as 22 to 18 ka (62)…”
Inching back to the LGM.
“…The evidence for humans in the Americas even earlier than 15 ka is less secure, but recently has been presented for four sites: Cactus Hill (Virginia), La Sena (Nebraska), Lovewell (Kansas), and Topper (South Carolina). Cactus Hill is a sand-dune site with late prehistoric, Archaic, and Clovis levels. Potentially older artifacts, including small prismatic blade cores, blades, and two basally thinned bifacial points were recovered 10 to 15 cm below the Clovis level (65). Three 14C dates ranging from 20 to 18 ka are reported from the levels below Clovis, but there are also dates of 10.3 ka and later. Charcoal samples were not recovered from hearth features but occur as isolated fragments at the same level as the artifacts. The younger dates indicate translocation of charcoal from overlying sediments, and the older charcoal could be derived from sediments underlying the cultural layer (59, 63), but luminescence dates on the aeolian sands correlate with the older 14C results and indicate minimal mixing of the sediments (66). Even though much information has yet to be published about this site, the potential presence of a biface and blade assemblage stratigraphically below the site’s Clovis assemblage is compelling…”
Ditto.
“…An even older occupation has been proposed based on taphonomically altered mammoth bones at the La Sena and Lovewell sites that date from 22 to 19 ka (67). Neither site has yielded stone tools or evidence of butchering; however, many of the leg bones display percussion impact and flaking, which suggests that they were quarried and flaked by humans while they were in a fresh, green state, within a few years of the death of the animals. Clovis people periodically flaked bone in this fashion, as did Upper Paleolithic Beringians (2, 22); however, in those contexts humans left behind stone tools, whereas at La Sena and Lovewell stone tools are absent…”
Ditto. Old Crow and Bluefish Caves come to mind.
“…Humans possibly colonized the Americas before the LGM. They occupied western Beringia by 32 ka, and no glacial ice sheets would have blocked passage through western Canada during this relatively warm time. However, there is still no unequivocal archaeological evidence in the Americas to support such an early entry…”
Plausible but not “proven”. Leaving the door open.
“…Clovis could have originated south of the continental ice sheets, and the dense Clovis quarry campsites in the southeastern United States may be the result of a longer occupation there than in other regions…”
I assume Texas is included in this definition of “southeastern United States”.
“…The peopling of the Americas debate is far from resolved. To move forward, we must continue to take an interdisciplinary scientific approach to the problem. Archaeological investigations will provide the empirical evidence of the first Americans, but this evidence must be objectively and rigorously evaluated...The sparse evidence for pre–13 ka occupation of the Americas may be a problem of sampling and artifact recognition…”
http://www.sciencemag.org/cgi/content/full/319/5869/1497_________________
Charlie Hatchett
PreClovis Artifacts from Central Texas
www.preclovis.com http://forum.preclovis.com
