[OR_Archaeology] Oregon caves yield evidence of continent's first inhabitants

[Susan White]

>From Nature News (Nature.com) 

Oldest American artefact unearthed
Oregon caves yield evidence of continent's first inhabitants.
by Rex Dalton

Archaeologists claim to have found the oldest known artefact in the
Americas, a scraper-like tool in an Oregon cave that dates back 14,230
years.  

The tool shows that people were living in North America well before the
widespread Clovis culture of 12,900 to 12,400 years ago, says
archaeologist Dennis Jenkins of the University of Oregon in Eugene. 

Studies of sediment and radiocarbon dating showed the bone's age.
Jenkins presented the finding late last month in a lecture at the
University of Oregon. 

His team found the tool in a rock shelter overlooking a lake in
south-central Oregon, one of a series of caves near the town of Paisley.


Kevin Smith, the team member who uncovered the artefact, remembers the
discovery. "We had bumped into a lot of extinct horse, bison and camel
bone – then I heard and felt the familiar ring and feel when trowel
hits bone," says Smith, now a master's student at California State
University, Los Angeles. "I switched to a brush. Soon this huge bone
emerged, then I saw the serrated edge. I stepped back and said: 'Hey
everybody — we got something here.'"

Coprolite controversy

Whether the cave dwellers were Clovis people or belonged to an earlier
culture is uncertain. None of the Clovis people's distinct fluted spear
and arrow points have been found in the cave. 

"They can't yet rule out the Paisley Cave people weren't Clovis," says
Jon Erlandson, an archaeologist at the University of Oregon who wasn't
involved in the research.

The only other American archaeological site older than Clovis is at
Monte Verde in Chile, which is about 13,900 years old.

Last year, Jenkins and colleagues reported that Paisley Cave
coprolites, or fossilized human excrement, dated to 14,000 to 14,270
years ago (1). That report established the Paisley Caves as a key site
for American archaeology.

Analysis of ancient DNA marked the coprolites as human. But in July,
another group argued that the coprolites might be younger than the
sediments that contained them (2).

This team, led by Hendrik Poinar of McMaster University in Hamilton,
Ontario, also questioned the 2008 report because no artefacts had been
found in the crucial sediments. The Oregon team strongly disputed the
criticisms (3).
Laid to rest?

The dating of the bone tool, and the finding that the sediments
encasing it range from 11,930 to 14,480 years old, might put these
questions to rest. "You couldn't ask for better dated stratigraphy,"
Jenkins told the Oregon meeting.

"They have definitely made their argument even stronger," says Todd
Surovell, an archaeologist at the University of Wyoming in Laramie who
was not involved in the research.

Other researchers questioned whether the cave's inhabitants would have
been mainly vegetarian, as the coprolites suggested (4). In his recent
lecture Jenkins noted other evidence reflecting a diet short on meat but
including edible plants such as the fernleaf biscuitroot, Lomatium
dissectum.

In late September, a group of archaeologists who study the peopling of
the Americas met with federal officials and a representative of the
local Klamath tribe to review the evidence at Paisley Caves. The
specialists spent two days examining sediments, checking the tool, and
assessing other plant and animal evidence.

"It was an impressive presentation," says David Meltzer, an
archaeologist at Southern Methodist University in Dallas, Texas, who
attended the meeting. "This is clearly an important site, but there are
some tests that need to be done to seal the deal." One key, he says, is
to better understand how the specimens got to the cave. 

References
         1. Gilbert, W.T.P. et al. Science 320, 786-789 (2008).
         2. Poinar, H. et al. Science 325, 148 (2009).
         3. Rasmussen, M. et al. Science 325, 148 (2009).
         4. Goldberg, P., Berna, F. & Macphail, R.I. Science 325, 5937,
148 (2009).