[Preview] I'll try another real-time blog for America's Stone Age Explorers, the Nova episode that airs Tuesday November 9 at 8:00 p.m. on PBS. Here's the online overview of the show from the PBS website, noting Tom Dillehay's pre-Clovis finds at Monte Verde in Chile as well as the epochal Pleistocene megafaunal extinction. I figure it's always worth my time to learn more about the principal ancestors of the American Indians (and of all Native Americans). Feel free to add your comments as the show proceeds. Kickoff at 8 o'clock sharp, California time, on this thread--I'll add paragraphs here as the show proceeds.
[8:10] Out of Africa came modern humans, but there were barriers to getting to the Americas. Clovis spearpoints--found in all 48 states--tell us when the Clovis people first flourished, but when did they get here, where did they come from, and where did they get their Clovis toolkit? So effective were these spearpoints they have been held out as the explanation for the rapid extinction of big mammals in North America about 13,500 years ago (the megafaunal extinction). There's not much before Clovis artifacts, so answering the when and where questions is a real challenge.
[8:20] Receding sea levels, the land bridge from Asia to Alaska, and the emergence of the ice-free corridor through glaciated Canada to verdant America about the time the Clovis culture exploded onto the scene--this was the standard story until a few years ago. Problem: new sites are finding artifacts predating or otherwise contradicting the standard "Clovis First" (CF) theory. Meadowcroft, a site in New England, gives artifacts going back to 16,000 BC. Other pre-Clovis artifacts emerged, despite opposition by CF supporters. How could pre-Clovis immigrants get past the ice? Heaton and Dixon think they might have come by boat, picking their way down the Alaskan coast where glaciers, it appears, did not cover everything but left pockets or long sections of exposed and temperate coastline, which they have supported with cave excavations. Dillehay's Monte Verde excavations in Chile also support pre-Clovis peopling of the New World. But what exactly is the new origins theory that might replace the CF model?
[8:30] Enter the mitochondrial DNA guy. Initial evidence pointed to Asian populations, but of the four main mitochondrial lines (cleverly named A, B, C, and D) three diverged over 20,000 years ago, much too old for the standard CF story. In addition, following the Clovis points themselves unearthed startling evidence: they didn't come from Asia. Brace yourselves--they came from France! Seems Solutreans, ancient Frenchmen, were making spearpoints remarkably like Clovis points 20,000 years ago, using the same overstrike technique. Yes, these guys (or their descendants) painted the caves there, too.
[8:40] But the Solutreans were kaput by 18,000 BC and Clovis points didn't show up until 13,000 BC. Solution--dig more. Cactus Hill is a site which disgorged intermediate points, predating standard Clovis sites. Problem--how to navigate thousands of miles of the frigid Atlantic? Solution--ask les esquimaux, who showed tricks (using natural materials) for staying warm and boating around icy waters in canoe-like boats. This is an argument for plausibility of the hypothesized Solutrean migration, but plausibility doesn't do much to covert critics. But CF supporters need to see a lot more than supposedly intermediate Cactus Hill points and Eskimos in boats to link Clovis to the Solutreans.
[8:50] More from the DNA guy, who finds a mitochondrial X line in certain Native American populations (what happened to E through W?) that seems to derive from European ancestors. But how does one rule out X being present in ancient Asian populations and simply having died out in the intervening millenia? And who's to say clever Clovis Native Americans needed to import ancient French technology to figure out how to make good spearpoints? Would you buy a Peugot if you could design your own Chevy? Sure enough, Gault, Texas has great rock for toolmaking and shows plenty of promising artifacts revealing broader patterns of hunting and gathering, even trading. It suggests that Clovis points emerged from a broad and developing pre-Clovis culture rather than as the key piece of a culture obsessed with hunting big game.
[9:00] Good news--the bottom line is that present evidence suggests Clovis didn't come from France, it was home-grown right here in North America. The emerging new theory goes something like this: Pre-Clovis peoples came much earlier than we used to think, got to know the place, found nice, easy-to-fashion rock in a few places like Gault from which they made knives for meat and blades for grass, and eventually developed the breakthrough Clovis spearpoint.