Friday, October 21, 2011

Before the Clovis

Today's Peninsula Daily News (front page no less!) reported on an investigation that demonstrated that Carl Gustafson's conclusion in the 1970's, that a spear tip found lodged in a mastodon bone recovered in Sequim, WA, pre-dated the Clovis cultures that were previously thought to have populated North America. The investigation, published in Science, demonstrates once more that the stories we tell ourselves about how Homo sapiens populated North America are probably wrong.

The thing that it made me think of, though, is the phenomenal morphologic change that these pre-Clovis people must have been experiencing at the same time they were sending a spear into a mastodon 13,800 years ago near Sequim. Retreat of the continental glaciers happened just 1000 years previously, and the land was still actively rebounding after bring freed of the massive weight of ice. Between about 14,500 and 13,500 years ago, the sea level relative to the land in the Strait of Juan de Fuca dropped by ~150 m. In other words, EACH YEAR the sea was dropping by almost half a foot on average (see below a sea level curve for the Strait of Juan de Fuca, adapted from Mosher and Hewitt, 2004).

At the time that the mastodon was speared the sea was close to 200 feet lower than it is now, meaning that the shoreline would have extended far out beyond the modern-day Dungeness Spit, Ediz Hook and Protection Island, and that the mastodon's final resting spot would have been hundreds of feet in elevation and miles away from the coast. The Strait of Juan de Fuca would have been a much narrower water body, and Vancouver Island would have been almost within spitting distance of the Olympic Peninsula.

These observations may suggest something about the pre-Clovis people. Were the pre-Clovis people a coastal people in the same way that the Northwest natives are, reliant on marine resources? It is hard to imagine a very stable or productive intertidal ecosystem in an environment of such dramatic sea level change. Or were they inland hunters, relying on the big game that foraged on the post-glacial tundra? I would give a lot to go back and see that landscape...

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