The first humans who ventured into North America crossed a land
bridge from Asia that is now submerged beneath the Bering Sea, and then
may have traveled down the West Coast to occupy sites in Oregon and
elsewhere as long as 14,000 to 15,000 years ago.
Now a new study has found that the West Coast of North America may
have looked vastly different than scientists previously thought, which
has implications for understanding how these early Americans made this
trek.
The key to this new look at the West Coast landscape is a fresh
approach to the region’s sea level history over the last several
thousand years. Following the peak of the last ice age about 21,000
years ago, the large continental ice sheets began to retreat, causing
sea levels to rise by an average of about 430 feet. When the ice was
prominent and sea levels were lower, large expanses of the continental
shelf that today are submerged were then exposed.
As the melting progressed and sea levels rose, likely archaeological sites along the coast were submerged.
Most past models have assumed that as the massive North American ice
sheets melted, global sea levels rose in concert – a phenomenon known as
“the bathtub model.” But the authors of this new study, which was just
published in the Journal of Archaeological Science, say sea level rise
does not happen uniformly. [...] oregonstate.edu via phys.org
Related: Coastal paleogeography of the California-Oregon-Washington and Bering Sea continental shelves during
the Latest Pleistocene and Holocene: Implications for the archaeological
record.
jueves, 28 de agosto de 2014
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