NOF Research Theme: Ancient Shores Of The Great Lakes

In 2004 we embarked on a multi-year investigation of ancient drowned shorelines in the Great Lakes.  Unknown to many residents of the Region is that these massive bodies of water have undergone huge changes in their levels since their creation from melting glaciers some 14,000 years ago.  For instance, past water levels in Lakes Huron and Michigan have been hundreds of feet higher and lower than at present. As a result their shorelines have changed drastically.

An NOF diver photographs the wall of an ancient river channel over 100 feet deep in Lake Michigan.

Coastal features of 7,000 to 11,000 years ago are now submerged as much as 400 feet deep, and consequently have been protected from the eroding effects of time.  One fascinating result is that the well-preserved remains of prehistoric forests — stumps and logs — can be found deep underwater.  Perhaps even relics of human habitation will be found on the lake bottom as well.

The Huron Ridge.  Most of our underwater investigations in 2006 and beyond will be focused on the Thunder Bay area and the nearby Lake Huron Ridge.  Using hi-tech tools of deep water exploration we will examine little-known features of ancient drowned shorelines to determine the details of their structure, the forces that shaped them, and the aquatic life that now inhabits them.  Of course, there is always the chance that our investigation will also turn up some unknown shipwreck or other relic of the prehistoric Great Lakes.​

The Huron Ridge, a submerged limestone formation, extends across the lake for over 100 miles between Alpena, MI and Ontario, CAN.  In mid-lake, the ridge rises nearly to the surface a Six Fathom Bank (arrow).  In some places along its northern side, steep cliffs descend to depths of over 500 ft.
During a much lower stage of Lake Huron the underwater ridge formed a land bridge across the lake for perhaps 2,000 years.
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