At the close of the last Ice Age about 13,200 years ago glacial ice formed a dam across the valley of the East Branch Ausable River creating a series of lakes that overflowed into adjacent watersheds through mountain passes.
This was during the late Wisconsinan glaciation in the final stages of the great continental Laurentide Ice Sheet’s retreat north from the Adirondack Mountains.
Generations of geologists have studied these areas since the 1800s and worked to unravel the complex history of a melting glacier and large bodies of water that never existed in the historical record.
Over the past several decades Dr. David Franzi, recently-retired geology professor at SUNY-Plattsburgh, has built on the foundational work in this region and prepared maps that show the limits of the glacial lakes and the outlets where they spilled into neighboring watersheds.
The Ausable Freshwater Center will host a tour to visit sites which help tell the story of these ancient lakes and the legacy of sediment they left behind.
The Center’s stream restoration manager Gary Henry will use these maps to guide a trip through the East Branch Ausable Valley and to help participants visualize the long-vanished glacier and its effects on the landscape.
The tour is scheduled for Wednesday September 24th and space is limited.
Participants will meet in Au Sable Forks at 10 am and be driven to the tour sites in a passenger van by Ausable Freshwater Center staff. The tour is expected to last approximately 4-5 hours.
For questions and to register email events@ausablecenter.org or call 518-637-6859. Expect an email the week before the tour to confirm details and provide more information.
Read more about geology in New York State.
Illustration: Map of Glacial Lakes in the Valley of the East Branch Ausable River courtesy Dr. David Franzi; Map of recession of the last ice sheet in New York and New England (Ernst V. Antevs, 1922).
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