Glacial Erosion
Definition of a Glacier
 A glacier is a large mass of ice that moves
slowly over land (a river of ice).
Nifty Glacier Facts
 Glaciers grow and recede as the climate
changes.
 Glaciers cover 10% of all land area.
 Glaciers hold 75% of the world’s freshwater.
 The Antarctic Ice Sheet is over 40 million years
old.
 Glaciers can be found on nearly every
continent.
Types of Glaciers
 Two types of glaciers:
 continental glaciers cover much of a
continent.
 valley glaciers form in a mountain range
and are often long and narrow.
Continental
Valley
Formation of Glaciers
 Glaciers form in areas where more snow
falls than melts.
 Once the glacier gets heavy enough,
gravity causes it to flow downslope.
Types of Glacial Erosion
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U-shaped valley
Moraine
Striations
Glacial lake
U-Shaped Valley
 A glacier is so heavy
that it scours out a
path through the
landscape as it
moves.
Moraine
 A moraine is a deposit of glacial till that is left
behind after the glacier recedes.
Striations
 Striations are
grooves cut in the
rock as a glacier
carves its way
through an area.
Striations provide a
major clue that
glaciers were in an
area
Glacial Lakes
 A glacial lake is an
old basin that has
been carved by a
glacier that is now
filled with water.
Other Notable Glacial
Facts:
 Other notable
features include;

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Icebergs
Hanging Valleys
Great Lakes
Ice caves
Icebergs
 Icebergs are chunks
of glaciers that have
fallen off the main
glacier into the
ocean.
 “Calving” is the term
for an iceberg
breaking off a glacier.
Only 10% of an iceberg is
visible above water.
Hanging Valley
Ice Caves
Ice Ages
The last great Ice Age began about
70,000 years ago and ended about 10,000
years ago.
97% of what is now Canada and much of
what is now the U.S. was covered with
glacial ice.
Glaciers and the Ohio
River
 The Teays River system existed before
the glaciation of the ice age.
 The glaciers carved away the Teays and
left a large lake that eventually drained,
ultimately creating the Ohio River
drainage basin
 The Great Lakes were
made from receding
glaciers. The glacial
melt-water filled in the
basins created by the
weight of the ice.
 The basins are now
gradually uplifting.
 The Great Lakes hold
20% of drinkable water
on Earth.
Fun with Glaciers!
Glacier National Park