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Glacial Geology of the Finger Lakes (with a focus on Honeoye Lake). Honeoye Valley Association Annual Meeting Saturday, July 13, 2019.
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Glacial Geology of the Finger Lakes (with a focus on Honeoye Lake)
Honeoye Valley Association Annual Meeting Saturday, July 13, 2019 Dr. Bruce GilmanDepartment of Environmental Conservation and HorticultureFinger Lakes Community College3325 Marvin Sands DriveCanandaigua, New York 14424Bruce.Gilman@retiree.flcc.edu
Acknowledgements • Dr. Richard Young, SUNY Geneseo • Dr. David Barclay, SUNY Cortland • Dr. Henry Mullins, Syracuse University and • Herman Leroy Fairchild, University of Rochester
THE PLEISTOCENE,“GREAT ICE AGE” A Very Different North America 20,000 years ago
Ocean levels fell by over100 meters (300 feet)! A cycle that repeated itself several times during the Great Ice Age
Warmer & less ice Interglaciations Glaciations Colder & more ice Pleistocene Ice Ages starting ~2.5 million years ago ending 10,000 years ago Raymo, 1992
How extensive? • 10% of our modern landscape is covered by glacial ice. • During the Great Ice Age, 32% of the global land surface was covered!
Today Quaternary North America - Ron Blakey
Greenland IS 20,000 years ago Laurentide Ice Sheet Quaternary North America - Ron Blakey
Honeoye Regionat the peak of glaciation Antarctica - Kevin McMahon
Ice Sheet Marginadvancing across upstate NY Lake Uplands
Selective Linear Erosion • Glacial ice has a preference to move in pre-existing stream valleys aligned with basal flow direction – it’s the area of least resistance! • Any meanders in the original stream flow pattern are straightened out – glacial ice does not bend!
Ontario basin R S G C I H B A Finger Lakes Formation Story(pre-glaciation drainage patterns)
Ontario basin R S G C Proglacial lakes I Proglacial lakes H B A Finger Lakes Formation Story(ice sheet advance)
Ontario basin R S G C I H B A Finger Lakes Formation Story (ice sheet maximum)
Ontario basin R S G C I H B A Finger Lakes Formation(Valley Heads Moraine deposition)
Ontario basin R S G C I H B A Finger Lakes Formation(Drainage Divide Today)
Water Erosion V-shaped rocky stream bed Ice Erosion U-shaped glacial sediment fill
The Finger Lakes Region contains 28 broad U-shaped glacial troughs, 11 of these valleys are doubly dammed (north and south ends) by moraine deposits and contain water!
Alaska – Ice Park Campground Glacial Lake Honeoye Landscape, 12,000 years ago
Migrating herds of large herbivores I couldn’t resist – great movie!
With the Predators came the first Americans, Stone Age hunters
THANK YOU for attending today’s annual meeting