Thursday, August 10, 2006

Local mammoth in the news
A local woolly mammoth may have just jumped in importance according to stories in both Seattle papers this morning.

The mammoth is the central focus of a dig near Selah in the southern part of the state. The dig, now completing its second season, has so far excavated about a third of the mammoth. While mammoth finds aren’t that rare in the northwest, this is one of the most complete ever found in the region, so Dr. Pat Lubinski and his team from Central Washington University (in Ellensburg, about 40 minutes north of the dig) aer being especially careful excavating it.

Last year they dated one of the leg bones of the mammoth at 16,000 years old. The date is what makes it newsworthy today. In the course of uncovering the mammoth this season, they have also uncovered a bison leg and a flake from a stone knife. The most accepted theory for the peopling of the Americas has Stone Age hunters entering the middle of North America 13 - 14 thousand years ago. Pushing that date back another two to three thousand years would be revolutionary.

The standard model of human arrival in the Americas was developed in the first half of the last century using data from geology and archaeology.

Geologists believed that during the ice ages, Alaska was attached to Eastern Siberia because sea level dropped when so much water was locked up in the ice caps. At the same time, Alaska was separated from the rest of North America by those ice caps. Two primary ice sheets covered most of Canada at the peak of the ice ages: the Laurentian, which spread out from Hudson's Bay, and the Cordilleran, which spread out from the western costal mountains. The two met in Alberta, just east of the Rockies. Meanwhile, Alaska was mostly ice free because the costal mountains stopped the precipitation necessary to form glaciers. It was dry, cold grassland.

Archaeologists discovered that people arrived in the connected land of Eastern Siberia and Alaska, a region they call Beringia, during the last ice age. Until recently, the earliest well-dated sites south of the ice were the Clovis sites of Colorado and New Mexico.

From these bits of data a narrative theory was formed. Hunters from Asia arrrived in Beringia during the last ice age. When the ice age began to end, the seas rose splitting Beringia into Siberia and Alaska. At the same time, the North American ice sheets separated and opened a path through the Yukon and Alberta into the middle of North America. With the advent of radioactive dating after World War Two, it was possible to date the Clovis culture to 11,500 years BC, which seem to fit very nicely with the end of the ice age.

Although generally accepted--you probably learned it in school--the Beringia-Clovis theory has never completely been without critics. Despite looking, archaeologists have never been able to find evidence of people using the ice-free corridor in Alberta. As more dates have come in, it has become unclear whether or not the corridor was open in time for the Clovis hunters. Finally, a number of controversial sites have been excavated over the years that appear to be older than Clovis. The most credible of these is at Monte Verde in southern Chile. The ice free corridor would be completely impossible for anyone before Clovis, so how could the first Americans have arrived if they didn't walk down from Alaska?

In the nineteenth century, writers had no problem answering that question. The first Americans were clearly Egyptians, Phoenicians, Chinese, Africans, Welsh, or the ten lost tribes of Israel who sailed over. None of these theories work to answer the new dating problems as their epic sailing adventures would have occurred too late. That leaves Atlanteans, space aliens, or something new. Despite a hard-core minority holding out for the Atlanteans and space aliens, most archaeologists have opted for the something new category.

Most of the sites older than Clovis have two things in common: they aren't as well dated and they are close to the sea (there are, of course, lots of exceptions). The new theory challenging Clovis looks at the west coast of North America. At the peak of the ice ages the Cordilleran ice sheet reached down toward the Pacific Ocean which was about 600 feet lower than it is now. The ice sheet would have met the sea much as it does in Greenland today, coming down valleys as tongues of ice leaving unglaciated ridges and larger areas near the water.

Some archaeologist believe a costal people might have traveled the length of both Americas living on the wealth of the tidal areas without penetrating the interiors of the continents until they had filled the coast. In this way, It makes sense for Monte Verde to be older than Clovis. The problem in proving this theory is that most of the evidence is on the old coastline 600 feet beneath the Pacific.

This is where the Selah find comes in. If North America was populated from the West Coast by fishermen, the first places that they would have entered would have been places where their skills were still useful. Places like the Columbia River. Selah is about two hundred miles up the Columbia. If the knife flake is 16,000 years old, it will give a big boost to the coastal theory.

However, there is no reason to believe that the knife flake is as old as the mammoth. Just because two things are found next to each other doesn't mean they were put there at the same time.

Lubinski and his team need to do some very careful stratiographic work to date the flake. Even then, it will still be controversial. The best evidence would be to find cut marks on the mammoth bones. When the Clovis sites were being investigated during the last century, several spear points were found with mammoths, but the archaeological community didn't really accept the idea that early Americans killed mammoths until a spear point was found embedded in a mammoth bone in Naco, Arizona in 1952.

We won't know the full story of the Selah mammoth anytime soon. Dr. Lubinski is closing up the dig for the season. He has to get back to Ellensburg and prepare for the fall semester. All winter, he and his students will be going over every bit of evidence that they brought back from Selah. I'll be watching and listening for news.

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