geomancer
03-24-2011, 07:04 PM
https://www.sciencemag.org/content/331/6024/1512.full
Science 25 March 2011:
Vol. 331 no. 6024 p. 1512
DOI: 10.1126/science.331.6024.1512
Texas Site Confirms Pre-Clovis Settlement of the Americas
Heather Pringle*
Heather Pringle is a contributing editor at Archaeology magazine.
Very ancient stone tools help confirm what many have long suspected: Clovis hunters, with their distinctive spear points, were not the first to people the Americas.
Near the headwaters of a small creek, a group of hunter-gatherers made their camp and began to craft stone tools. The riverbanks rang with their blows, as they struck flakes off chert nodules to create tools for cutting hard materials such as bone; they also knapped small blades for processing hides. They left thousands of sharp stone flakes and chips discarded on the ground.
At one time or another, similar scenes have played out almost the whole world over. But the remarkable thing about this one, as detailed on page 1599 of this issue, is that it happened near Buttermilk Creek, Texas—about 15,500 years ago. That's long before the Clovis hunters, once thought to be the very first people in America, had appeared. Lead author Michael Waters of Texas A&M University in College Station says this site “tells us for once and for all that we can abandon this Clovis-first model.” The ancient tools also offer a first glimpse into how the distinctive fluted Clovis points may have developed over millennia.
Although some previous claims of pre-Clovis artifacts have been controversial, other archaeologists say the new research is highly convincing. “The many distinct and superbly documented lines of evidence … offer pretty unequivocal confirmation that people were in interior North America south of the ice sheets before the Clovis radiation,” says David Anderson of the University of Tennessee, Knoxville, founder of the online Paleoindian Database of the Americas.
Archaeologists have been locked in an acrimonious debate over the early peopling of the Americas for nearly 30 years. Advocates of the Clovis-first theory argued that the big-game–hunting Clovis people were the first to arrive from Asia, about 13,200 years ago. Other archaeologists reported nearly two dozen pre-Clovis sites in North America. In each case, however, the evidence was incomplete or flawed. Even so, says archaeologist Dan Sandweiss of the University of Maine, Orono, the pre-Clovis theory “has been getting more and more traction.” But advocates have had trouble pointing to a particular North American site that offered strong proof in one place.
The new paper claims to change all that. In 2006, Waters and his team began excavating at the Debra L. Friedkin site in central Texas, not far from a known Clovis site. The site lies near a year-round water supply and close to an abundant source of high-quality chert for toolmaking. Repeated incremental deposits of clay from flooding over the millennia offered good preservation.
As the team dug down into the clay, they found a sequence of cultural horizons, each with diagnostic stone tools in correct stratigraphic order, ranging from Late Prehistoric artifacts in the uppermost horizon to Folsom, Clovis, and finally pre-Clovis in the three lowest levels. But they found no charcoal or other organic material, which is often poorly preserved in this region, and so had no way to radiocarbon-date the layers.
The team opted to use optically stimulated luminescence (OSL), a technique that measures the amount of light energy trapped in quartz and feldspar grains in the clay and dates the last time they were exposed to sunlight. The lowest tool-laden horizon dated to 15,500 years ago—more than 2 millennia before the first Clovis sites. And the dates of the overlying horizons correlated with those of their diagnostic tools. “The OSL dates are almost perfect top to bottom,” says archaeologist Dennis Jenkins of the Museum of Natural and Cultural History in Eugene, Oregon, who was not involved in the study.
The team did four other analyses, such as examining whether artifacts were sorted by size, to be sure that artifacts from upper levels had not fallen down into the pre-Clovis layer. “All [the analyses] pointed to an intact sequence,” says Sandweiss, another outsider familiar with the findings.
Use-wear studies on tools from the lowest layer reveal that the pre-Clovis people used the tools to work bone, wood, or ivory and to cut or process hides. And their blades, bladelets, and bifaces bear some important resemblances to the later Clovis toolkit, pointing to continuity between the two groups. “The thing I find really neat,” Waters says, “is that we found 12 [pre-Clovis] bifaces, and they were making them by bifacial reduction, similar to the technique used by Clovis people.”
Longtime Clovis-first advocate Gary Haynes of the University of Nevada, Reno, is impressed by the paper, saying that it includes key stratigraphic analyses missing from studies of other possible pre-Clovis sites in North America. And “there's no question that the artifacts are really stone tools,” he says, a problem raised at other pre-Clovis sites. “These are really things that could be technologically and logically ancestral to Clovis.” But Haynes isn't sure the tools date to pre-Clovis times and would like radiocarbon dates to be certain.
Despite such doubts, Anderson expects that the new findings will move studies of the first Americans into a new phase. “As more attention focuses on pre-Clovis lifeways, we can begin to get a better handle on many major questions: how did the colonization proceed, [and] how widely did these folks range over the landscape,” he concludes.
Science 25 March 2011:
Vol. 331 no. 6024 p. 1512
DOI: 10.1126/science.331.6024.1512
Texas Site Confirms Pre-Clovis Settlement of the Americas
Heather Pringle*
Heather Pringle is a contributing editor at Archaeology magazine.
Very ancient stone tools help confirm what many have long suspected: Clovis hunters, with their distinctive spear points, were not the first to people the Americas.
Near the headwaters of a small creek, a group of hunter-gatherers made their camp and began to craft stone tools. The riverbanks rang with their blows, as they struck flakes off chert nodules to create tools for cutting hard materials such as bone; they also knapped small blades for processing hides. They left thousands of sharp stone flakes and chips discarded on the ground.
At one time or another, similar scenes have played out almost the whole world over. But the remarkable thing about this one, as detailed on page 1599 of this issue, is that it happened near Buttermilk Creek, Texas—about 15,500 years ago. That's long before the Clovis hunters, once thought to be the very first people in America, had appeared. Lead author Michael Waters of Texas A&M University in College Station says this site “tells us for once and for all that we can abandon this Clovis-first model.” The ancient tools also offer a first glimpse into how the distinctive fluted Clovis points may have developed over millennia.
Although some previous claims of pre-Clovis artifacts have been controversial, other archaeologists say the new research is highly convincing. “The many distinct and superbly documented lines of evidence … offer pretty unequivocal confirmation that people were in interior North America south of the ice sheets before the Clovis radiation,” says David Anderson of the University of Tennessee, Knoxville, founder of the online Paleoindian Database of the Americas.
Archaeologists have been locked in an acrimonious debate over the early peopling of the Americas for nearly 30 years. Advocates of the Clovis-first theory argued that the big-game–hunting Clovis people were the first to arrive from Asia, about 13,200 years ago. Other archaeologists reported nearly two dozen pre-Clovis sites in North America. In each case, however, the evidence was incomplete or flawed. Even so, says archaeologist Dan Sandweiss of the University of Maine, Orono, the pre-Clovis theory “has been getting more and more traction.” But advocates have had trouble pointing to a particular North American site that offered strong proof in one place.
The new paper claims to change all that. In 2006, Waters and his team began excavating at the Debra L. Friedkin site in central Texas, not far from a known Clovis site. The site lies near a year-round water supply and close to an abundant source of high-quality chert for toolmaking. Repeated incremental deposits of clay from flooding over the millennia offered good preservation.
As the team dug down into the clay, they found a sequence of cultural horizons, each with diagnostic stone tools in correct stratigraphic order, ranging from Late Prehistoric artifacts in the uppermost horizon to Folsom, Clovis, and finally pre-Clovis in the three lowest levels. But they found no charcoal or other organic material, which is often poorly preserved in this region, and so had no way to radiocarbon-date the layers.
The team opted to use optically stimulated luminescence (OSL), a technique that measures the amount of light energy trapped in quartz and feldspar grains in the clay and dates the last time they were exposed to sunlight. The lowest tool-laden horizon dated to 15,500 years ago—more than 2 millennia before the first Clovis sites. And the dates of the overlying horizons correlated with those of their diagnostic tools. “The OSL dates are almost perfect top to bottom,” says archaeologist Dennis Jenkins of the Museum of Natural and Cultural History in Eugene, Oregon, who was not involved in the study.
The team did four other analyses, such as examining whether artifacts were sorted by size, to be sure that artifacts from upper levels had not fallen down into the pre-Clovis layer. “All [the analyses] pointed to an intact sequence,” says Sandweiss, another outsider familiar with the findings.
Use-wear studies on tools from the lowest layer reveal that the pre-Clovis people used the tools to work bone, wood, or ivory and to cut or process hides. And their blades, bladelets, and bifaces bear some important resemblances to the later Clovis toolkit, pointing to continuity between the two groups. “The thing I find really neat,” Waters says, “is that we found 12 [pre-Clovis] bifaces, and they were making them by bifacial reduction, similar to the technique used by Clovis people.”
Longtime Clovis-first advocate Gary Haynes of the University of Nevada, Reno, is impressed by the paper, saying that it includes key stratigraphic analyses missing from studies of other possible pre-Clovis sites in North America. And “there's no question that the artifacts are really stone tools,” he says, a problem raised at other pre-Clovis sites. “These are really things that could be technologically and logically ancestral to Clovis.” But Haynes isn't sure the tools date to pre-Clovis times and would like radiocarbon dates to be certain.
Despite such doubts, Anderson expects that the new findings will move studies of the first Americans into a new phase. “As more attention focuses on pre-Clovis lifeways, we can begin to get a better handle on many major questions: how did the colonization proceed, [and] how widely did these folks range over the landscape,” he concludes.