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The conventional view of the first
humans to reach the Americas is
that they arrived from Siberia, bundled
in furs and tromping across the steppes
of Beringia, no more than 13,500 years
ago. After crossing the land bridge, they
followed an open corridor between two
shrinking ice sheets into the continent’s
interior.
But recent geological and
paleoenvironmental studies, such as a
reconstruction of ice sheet ebb and
flow published in Science in 2017, have
suggested that this corridor would not
have been habitable until centuries later,
long after humans were already present
throughout the Americas. Plus, sites
from Chile to Florida have been dated
as at least 14,500 years old.
First proposed about a decade ago by
University of Oregon archaeologist Jon
Erlandson, the Kelp Highway Hypothesis
suggests that, millennia before the
inland Beringia land corridor opened,
humans could have followed resource-
rich paleocoastlines by boat. This route
would have taken them from Asia and
Siberia eastward along the southern
coast of Beringia, into the Americas,
and all the way to southern Chile. The
idea is gaining momentum.
“We’ve been talking about the ice-
free corridor for 80 years,” says Todd
Braje, California Academy of Sciences
archaeologist who believes a coastal
route was open at least 16,000 years ago
and possibly much earlier. “It is time to
explore other things.”
Part of the problem with investigating
a maritime route along Beringia’s
southern coast is the extreme
environment of the region today. Even
in the best weather, Arctic regions are
limited to very short (and expensive)
field seasons.
Several groups of researchers are
looking instead at areas along the
Pacific Coast, well south of Beringia,
where early seafarers might have come
ashore.
Braje and his colleagues, for example,
are in the final year of a four-year project
split between Southern California’s
Channel Islands and a second offshore
site in Oregon. On the northern Channel
Islands, multiple paleocoastal sites of
10,000 years or more have already been
documented. Erlandson, who is also
involved in the Channel Islands project,
has identified artifacts at one of the sites
that may be 18,000 years old.
The team is currently focused on
a shallow bay that would have been
protected from the Pacific’s pummeling
waves. Here, the sea level rose quickly;
rapidly deposited sediments preserved
features, such as river estuaries, that
would have been attractive to humans.
The team
has taken more
than two dozen core
samples from the most promising
areas and will analyze them for clues
to the lost paleoenvironment.
As they refine seafloor mapping,
landform recognition and core
analysis techniques, the researchers
are trying them out at the second
site, Heceta Banks, about 30 miles off
the coast of central Oregon.
“It’s a very different environment,
but the idea is to take Channel Islands
methods and test them there to see if
they work in different kinds of locations,
with the ultimate goal of refining
methods [that would] work along the
entire Pacific coast,” Braje says.
Riding a Kelp Highway:
The First Americans
15,000-plus years ago
60 DISCOVERMAGAZINE.COM
California’s Channel Islands would have been
different 16,000 years ago, when sea levels
were 330 feet lower than they are today.
The four northern islands would have been
a single landmass (shown above in red).
These 12,000-year-old projectile points
and crescent-shaped knives are examples
of the kinds of artifacts left behind by
early explorers of the Channel Islands.
Channel
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Though textbooks describe an
important human migration route
that crosses the Bering Strait,
it’s possible humans instead
followed the coastline, arriving
in the Americas by boat.
BERINGIA
NORTH
AMERICA