Sunday, December 18, 2005

 

Britain - Tools Found in Seashore Sediment Show Much Earlier Human Existence

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Washington Post
By Guy Gugliotta
December 15, 2005

A chance discovery on a routine field trip to England's Suffolk seacoast led to evidence that humans reached northern Europe 700,000 years ago, about 200,000 years earlier than previously thought, scientists said yesterday.

The recovery of 32 hand-worked black flint flakes from seashore sediment vindicated researchers who had sought for two centuries to unearth proof of human habitation in the fossil-rich lowlands bordering the North Sea.

"Every effort had failed to prove there were tools, and we assumed that people just weren't there," said paleoanthropologist Christopher Stringer of London's Natural History Museum, who is part of the 19-member team studying the deposits. "But absence of evidence does not necessarily prove evidence of absence."

The discovery showed that archaic humans crossed the Alps into northern Europe more than 200,000 years earlier than previous excavations had indicated, and only about 100,000 years after humans arrived in southern Europe, probably from Africa.

Reporting in the journal Nature, the team said the early settlers apparently took advantage of climactic conditions during a relatively warm "interglacial" period to dwell in fertile lowlands that formed part of a land bridge connecting what is now the island of Britain with the rest of Europe.

"It was warmer than it is today, a big delta with a fan of rivers," Stringer said. "It had a dry, mild Mediterranean climate, exotic beasts and lots of resources."

Stringer said it is unclear whether the settlers, probably a variant of the archaic human species known as Homo heidelbergensis, remained in England once they arrived, and suggested that subsequent "ice ages" may have driven them away.

"Colonization is risky," said Stony Brook University archaeologist John Shea, not a member of the British-led research team. "Think Jamestown, or the Sea of Tranquility. This may be permanent, or it may be a short pulse of settlement. What needs to happen is to fill in the gaps."

Stringer said the artifacts were discovered by accident during a field trip to the North Sea coast near Pakefield. Researchers for 200 years have explored the area's coastal sediment because of the rich variety of ice age animal and plant fossils encountered there. The exposed sediment changes continually because of shoreline erosion.

"Someone found a flint flake sticking out of a sediment layer," Stringer said. Fortunately, he added, the group included John J. Wymer, a well-known expert on Britain's stone age, "who identified it as a humanly-struck flake. That started the ball rolling."

Experts eventually found 32 flakes made by striking a flint stone core with another stone.

Stringer said at least one of the flakes had been retouched to sharpen the edges, while another was a sharpened flint stone "core."

Stringer said the flakes, one to two inches long, were "razor sharp" and had probably been used as knife or spear points. None had been shaped as a fist-size "hand ax," a technology known to human ancestors for at least 1 million years.

"It's possible that they didn't make hand axes because they didn't know how," Stringer said. "But there's no good local source of flint, either. What we're probably looking at are river cobbles."

Stringer said the team dated the find by using a variety of techniques and determined that the sediment had to be at least 700,000 years old -- older by 200,000 years than famous finds in Mauer, Germany, near Heidelberg, and Boxgrove, on England's southern coast.

No human remains were found with the Pakefield flints, but he suggested that the inhabitants were members of an archaic species that preceded Neanderthals, present in Europe around 200,000 years ago, and the arrival of modern humans about 160,000 years after that.


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