Age limit for dating sites kip steadmans guide to dating
As O’Shea looked at the map and envisioned what this ridge might have looked like in the past, he realized that around the end of the last Ice Age, some 9,900 years ago, it would not have been submerged.
Rather, it would have been a land bridge, with icy lakes on either side and the receding glacial ice sheet just a few hundred miles to the north.
“There’s only a 2,000-year window where it was dry land.
Then it was submerged and didn’t reemerge again.” Dating of the remains of ancient trees on the ridge based on wood samples and ancient pollen has shown that the land bridge would have indeed been a subarctic environment, says University of Texas at Arlington archaeologist Ashley Lemke, who has worked on the project for six seasons.
Any stone hunting structures that may have existed were likely either knocked down by later settlers or are impossible to distinguish from walls and rock piles created by modern inhabitants.
O’Shea thought that the ridge sitting beneath the waters of Lake Huron, now known as the Alpena-Amberley Ridge, could have acted as a time capsule.
Those charts showed that a rocky underwater feature known as Six Mile Shoal was actually a continuous underwater ridge stretching 112 miles from northeastern Michigan to southern Ontario.
And if herds of caribou had once migrated across this landscape, he reasoned, there were probably people hunting them.
“I thought we could find signs of those hunters.” Archaeologists have long suspected that since the Upper Midwest would have been an area attractive to these herds, the region’s prehistoric Ice Age inhabitants, known as Paleoindians, would have relied heavily on them. Acidic soils around the Great Lakes break down bones quickly, making it difficult to find the remains of caribou—or of any ancient animal—in the region.
The idea, O’Shea admits, was a little bit wacky, but he thought his reasoning was sound even if locating the remains of that caribou hunting culture posed a daunting challenge.
It would mean scanning hundreds of square miles of lake bed, 60 miles offshore.
In the spring, as the herds of caribou headed up the ridge to the northwest, the hunters would have engaged in a different style of hunting, working in larger groups to herd the caribou down through stone drive lanes and processing large amounts of meat.