Caribou Hunting in the Great Lakes?

We attended a fascinating lecture at our regional museum last week, and it's got me interested in ancient Great Lakes history.  So I'm doing a little research of my own and I'm gonna share it with you over a few posts while we wait for the endless cold temperatures of early April to go up!

Leonore Keeshig, of the Saugeen Ojibway First Nation, spoke on indigenous legends that tell the story of retreating glaciers and a time when the annual caribou hunt was important, in a landscape that would be described as arctic, about 9000 years ago.  It was a landscape that would befie your belief today as you sail over the waters of Lake Huron and Georgian Bay.

So bear with me while I give you some background and then I'll try to explain the essence of her message.  Otherwise you can just skip this post and wait for the next one.  I hope you can get used to these maps.  They're kind of skewed, with north in the upper right corner but I'll explain them.

The upper left corner of this widely published diagram, shows the glaciation of the Great lakes, when lobes of the continental ice sheet extended down into Lake Michigan and Lake Huron.  Two lakes of meltwater sat in the south end of today's Lake Michigan and Lake Erie, labelled by scientists as Lake Chicago and Lake Maumee.  Drainage was to the southwest, through Saginaw Bay and Chicago to the Mississippi.

In the upper right diagram, the glacier has retreated north, allowing for a huge glacial lake to form, encompassing both today's Lake Michigan and Lake Huron, and the tip of Georgian Bay, labelled glacial Lake Algonquin.  It still drained to the southwest, as drainage north or east was blocked by the ice.  The shoreline of that lake can still be traced, considerably higher than the lakes today, including right here in Meaford.

The lower left diagram is the interesting one.  As the ice retreated north the lakes reached a point where they could drain to the northeast, out through today's French River and North Bay, reversing the drainage pattern completely.  This left the glacial lakes at a much lower level than today's lakes.  A smaller lake occupied Lake Michigan, known as Lake Chippewa, and similarly a smaller lake occupied Lake Huron, known as Lake Stanley.

It is at this stage, somewhere between 7000 and 9000 years ago, that we find tantalizing evidence of indigenous life on dry land that is today submerged.

Let me first finish describing the diagram above.  In the lower right corner we have a map showing approximately today's Great Lakes.  The water level was a little higher, so the Lake Huron/Georgian Bay/Lake Michigan basin was inter-linked and known as Lake Nipissing; Lake Stanley has disappeared, but there is still drainage to the northeast, through North Bay.  We can find clear evidence of this old shoreline right here in Meaford; indeed, it's just two blocks from my house.

Let's take a closer look at that Lake Stanley and the lowest water levels of the Great lakes basin.

I had always assumed that the glacial lake levels were much higher than today's lake levels, and they gradually fell, from glacial Lake Algonquin to Lake Nipissing to today's lakes.  But it's not actually that simple.  Glacial lake levels actually fell to a very low level, as in Lake Stanley, and then rose again to the Lake Nipissing level, and then fell again to today's lake levels.  So we have a gigantic up and down pattern going on.

When drainage shifted to the northeast, the lowest levels of the lakes were reached, with rivers connecting Lake Chippewa, Lake Stanley, Georgian Bay and a small corner of what became Lake Superior.  The green areas here were dry land, extending the shoreline far out from today's pattern. 

Take a look at how the Lake Stanley basin was divided in two.  Turns out that band of green running through the middle of the lake was dry land too, an underwater ridge known today as the Amberly to Alpena Ridge.  That's where we'll pick up next post; hope you're still with me!