The Alpena-Amberley Ridge

At this point in understanding ancient Great lakes history, we will focus on the Alpena-Amberly Ridge under the middle of Lake Huron.  If you don't know what this is, you'd better go back and read the previous post.

About 20 years ago, Dr. John O'Shea, an archeologist at the University of Michigan, was looking at this bathymetric map of Lake Huron, and spotted that shallower ridge running from southeast to northwest through the lake, here highlighted by black dashed lines.  It came to be known as the Alpena-Amberly Ridge, for the names of the nearest towns on each end, and it has been a focus of underwater archeology ever since.

There have been lots of advances in underwater exploration in recent years, usually from trying to find shipwrecks, so there are good tools for underwater archeology.  O'Shea took advantage of these and initially used side-scan sonar, finding evidence of rock piles that appeared human-made.  

Caribou are known to travel in regular routes, based on patterns in today's Arctic.  There indigenous hunters build small rock cairns creating 'drive lanes', making hunting more successful.  We once crossed one of these hunting spots, while paddling down the Burnside River in the Arctic.  A pile of antlers bore witness to the successful hunt.

Next they used a remotely operated vehicle which they named 'Jake', as well as actual divers to assess the appearance of this ridge.  The structures they found looked like drive lanes which could have been used to funnel the animals by creating bottlenecks where Indigenous hunters would be more successful.  They also found hunting blinds and broken arrowheads.

This description also immediately reminded me of Head-Smashed-In Buffalo Jump in southern Alberta, a site we visited on our first big trip west with our kids in 1986.  People visiting this site are of course entranced by the cliff the buffalo jumped over, and the kill site below.  Even archeologists focus on the kill site, because that's where you find ancient artifacts.  

But the real action took place above the cliff.  Here men of the tribe placed rock cairns built up with sticks and brush to create long drive lanes that the buffalo followed.  The real work was in finding a convenient herd and gradually working them toward these drive lanes.  (It was a lazy young brave who hid below the cliff rather than join the runners who had his head smashed in).

In this, another version of a bathymetric map of Lake Huron, you are looking at the Lake Stanley phase of the Great Lakes, approximately 7000 - 9000 years ago, when the Lake Huron basin was divided in two, and water levels were much lower than today.  The Alpena-Amberley Ridge stands out clearly.

The research led by underwater archeologist Dr. O'Shea has discovered an ancient caribou route across this dry ridge.  And further, it has documented stone structures built by indigenous hunters at narrow points of the ridge and what appear to be hunting blinds.

The research was not over yet though.  By gathering sediment and analyzing it they were able to reconstruct the ancient landscape, or what they labelled the paleo environment.  That's the next story.

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