Geological Evidence of Glacial Activity in New York State

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Geological Evidence of Glacial Activity in New
York State
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The ice age in North America began about two
million years ago and ended about 6000 years ago.
During this period four major glacial advances
occurred. Deposits and glacial evidence may be
found in all northern states. But only in New
York can we find the latest glacial evidence.
Earlier glacial evidence has bin swept away.
This glacier that swept away all the evidence is
called the Wisconsin glacier. This took place
20,000 years ago. Many examples of evidence of
this glacier are visible today. n years ago and
ended about 6000 years ago.
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• GLACIER FACTS
• 20,000 years ago glaciers covered all of Canada
  and extended southward over the sites of Seattle,
  Chicago, and New York city.
• All of New York ,except for the Allegheny state
  park was once buried under ice more than one mile
  thick.
• The glaciers over road all of the Adirondack
  mountains including the highest mountain which is
  Mt. Marcy.
• Because of their great thickness and mass,
  glaciers completely override all land features
  even some times large mountains.

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• Today very few places have low enough average
  temperatures and sufficient snow fall for
  glaciers to form.
• Antarctica is covered by the largest glacier that
  is one and a half times as large as the United
  States.
• New Yorks Finger Lakes were carved out by
  glacial ice.
• Long Island is a 120 mile long out washed plain.
  It has no bedrock.
• Niagara Falls began when the Wisconsin Glacier
  melted.

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GLACIER TERMINOLOGY
Glacier is a body of ice showing evidence of
movement as reported by the presence of ice flow
line, crevasses and recent geologic
features. Glacial Advances is the net movement
of glacier terminus downvalley. Advance occurs
when the rate of glacier flow downvalley is
greater than its rate of ablation. Morainerock
debris deposited by a glacier. Striations are
the scratches etched in to the rock at the bed of
a glacier. Tillis the unsorted rock debris
deposited directly by the glacier without the
extreme reworking by meltwater. Also called
Glacial Till.
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ErraticBolder transported by a glacier that
generally differs from the bedrock beneath the
rock. Kettle depression in a glacial deposit
were outwash was deposited around a residual
block of ice. Kame A conical hill of sand and
gravel deposited by a melting glacier. Continenta
l Glacier ice sheet of continental
proportion. MeltWater water from ice and snow,
especially from a glacier
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This is a glacial erratic that shows evidence of
weathering and erosion
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Two erratics lined up in approximate direction of
ice flow
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May be a small kettle lake or pond, rounded edges
and poor drainage.
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A large erratic placed here by a glacier.
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Evidence of frost wedging since glacial
deposition.
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One side of this U-shaped glacial valley shows
glacial debris of all sizes
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U-shaped valley showing smooth side to the right.
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Unsorted, angular edged fragments deposited by
glacial ice.
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Young stream eroding through the glacial debris.
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Scratches on a rock caused by glacial till
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Another large erratic showing scratching going
in one direction.
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Evidence of weathering of erratic since the last
ice age.
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A different angle of this large glacial erratic
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Large erratic for this area but in the mid-west
the haystack boulders may be as large as a
house.
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Bibliography


Ramsey, William L. Modern Earth Science. Holt,
Rinehart and Winston Publishers NewYork,
1979. USGS. Glossary of Selected Glacier
Terminology. http//vulcan.wr.usgs.gov/gloss
ary/Glaciers/glaciers_terminology.html Van
Diver, Bradford B. Roadside Geology. Mountain
Press Publishing Company Missoula, 1985.