What really happened to the Mastodons?
The disappearance of the great Ice Age animals across the North American continent about 10,000 years ago has been a mystery to archaeologists and naturalists for nearly a century. Explanations for the sudden demise of the megafauna such as mammoths, mastodons and the giant ground sloth range from climate change to over hunting to disease. Below is an article that offers a new if not somewhat exotic view of events at the end of the last Ice Age in North America.
When It Rained Diamonds Scientists say jewels and metals found in Ohio tell of a world-changing explosion Monday, July 21, 2008 3:00 AM By Kevin Mayhood THE COLUMBUS DISPATCH NORTH BEND, Ohio — The theory is as wild as it is controversial: that a comet, which left no crater, exploded over Canada almost 13,000 years ago, wiped out the woolly mammoth and other land giants and nearly decimated the first known human culture in North America. “I thought that was a bunch of nonsense,” said Kenneth Tankersley, a University of Cincinnati anthropologist. But by the end of June, Tankersley was a convert. Now he says that he not only believes the scientists who came up with the theory, but “I’ve come up with their best evidence.” That evidence, he said, includes diamonds, gold, silver and copper and comet debris that his team found in Ohio in May and June and matched with the materials found in Canada.
The theory, including that the diamonds and metals rained from the skies, still is controversial and is attracting a lot of attention. One documentary on the subject has aired on the National Geographic Channel, and at least two others are in the works. (Others say these materials were carried into Ohio and elsewhere by glaciers.) Tankersley is writing a paper that he hopes to publish this year. The idea originated years ago with Allen West, a retired geophysicist from Dewey, Ariz., who said that an ice age was coming to an end when a comet broke up and exploded above the thick ice sheet that covered eastern Canada 12,900 years ago. In a paper published last year, West and his colleagues described an explosive force that lifted diamonds, gold, silver and copper from the ground and threw them into the atmosphere. The explosion, they say, set off massive forest fires and shock waves that sent the debris flying 400 mph across North America and as far as Ireland. Oceans were overwhelmed by melting glaciers and the debris blocked sunlight, reversing the warming trend. In turn, the Earth was cooled for an additional 1,300 years. “The bigger animals went extinct; smaller omnivores did the best,” West said, who has found comet debris from the Canada explosion across the United States and into Europe.
Some scientists think that the first known humans in North America, called the Clovis culture, overhunted mammoths and other “megafauna” into extinction, but West says those large mammals died off when the rapid climate change killed the plants they ate. Some scientists think that the Clovis population grew during this time, based on the number of artifacts found at archaeological sites across the country. Others, however, say their numbers dropped significantly when their main food sources disappeared. “It’s an exciting and sort of fun idea,” said Bradley T. Lepper, curator of archaeology at the Ohio Historical Society. “But associating (the comet’s impact) with the changing culture of the Clovis and extinction of the megafauna is a stretch.” Lepper is in the camp that thinks the Clovis population increased during that time and points to the high number of artifacts found across the region. Tankersley is in the opposite camp. He said he and his students found pieces of weapons, tools and other artifacts that suggest the Clovis shifted from hunting mammoths to relying on plants for food. That change, he said, caused the Clovis population to decrease. “Their technology went extinct because they were no longer hunting mammoths.”
Tankersley’s finds this year were resting a few inches beneath the surface in a remote part of Shawnee Lookout, a park west of Cincinnati. East of the city, near Newtown, Tankersley also has found copper, gold, silver and tiny diamonds as well as pieces of the Canada comet. He found more of the same in Sheriden Cave, in Wyandot County. The metals were found in a layer of earth that includes charcoal and burnt remains of a giant beaver and pig. Carbon dating suggests that the layer is 12,900 years old, right when the comet was supposed to have exploded. West said some diamonds were blown out of Canada by the explosion and others formed in Ohio and elsewhere when the carbon from burning trees was pressurized by the initial shock wave or aftershocks. Both West and Tankersley have linked the debris found here and elsewhere to the event in Canada by tests that show they share the same age and composition.