Saturday, March 26, 2011

STONE TOOLS FROM CALIFORNIA'S CHANNEL ISALNDS

A collection of delicate stone tools discovered on California's Channel Islands (USA) indicate that early humans in the Americas were hunting local waterfowl some 11,200 to 12,200 years ago. "The points we are finding are extraordinary," Jon Erlandson, director of the University of Oregon's Museum of Natural and Cultural History said. Made primarily from local chert using a bifacial technique, the tools "are ultra thin, serrated and have incredible barbs on them. It's a very sophisticated chipped-stone technology," he explained. "This is among the earliest evidence of seafaring and maritime adaptations in the Americas," Erlandson said. Previous evidence had suggested only prolific local hunting around the islands from some 8,000 to 10,200 years ago.

Fifteen stone crescents, 52 small stemmed barbed points and a sampling of other
tools from Santa Rosa Island, along with 31 crescents, 32 stemmed points and 23 Amol points found on San Miguel Island, are described in a paper published online March 3 in Science. "We think the crescents were used as transverse projectile points, probably for hunting birds," Erlandson said.

The artifacts are associated with the remains of shellfish, seals, geese, cormorants and fish; they were recovered from three sites that date to the end of the Pleistocene epoch on Santa Rosa and San Miguel islands, which in those days were connected as one island off the California coast, and the researchers suggest that these areas might have been seasonal hunting grounds. Sea levels then were 50 to 60 meters (about 160-200 feet) below modern levels. Rising seas have since flooded the shorelines and coastal lowlands where early populations would have spent most of their time.

Torben Rick, curator of North American Archaeology at the Smithsonian Institution and co-author of the new paper, added that the tools "show that very early on, New World coastal peoples were hunting such animals and birds with sophisticated technologies that appear to have been refined for life in coastal and aquatic habitats." The early inhabitants might have also been engaged in trading networks. One Santa Rosa Island tool was made of obsidian from a volcanic area some 300 kilometers away.

The findings suggest that these early islanders were not members of the land-based Clovis culture, Erlandson said. No fluted points have been found on the islands. The researchers also note that the shape of the tools echoes the shapes of those found on the Pacific coast of South America and as far away as Japan, suggesting that the early Californians were not a western branch of the Clovis culture, but rather from a more coastal diaspora that rimmed the Pacific.

Six years ago, Erlandson proposed that Late Pleistocene sea-going people may have followed a 'kelp highway' stretching from Japan to Kamchatka, along the south coast of Beringia and Alaska, then southward down the Northwest Coast to California. Kelp forests are rich in seals, sea otters, fish, seabirds, and shellfish such as abalones and sea urchins. Taken together, the tools found recently by the researchers reveal "another extension of the diversity of Paleoindian economies," Erlandson said. The next challenge, Erlandson and Rick noted, is to find even older archaeological sites on the Channel Islands, which might prove that a coastal migration contributed to the initial peopling of the Americas, now thought to have occurred two to three millennia earlier.

Edited from EurekAlert!, Scientific American (3 March 2011)
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