Page 105 - Super Earth Encyclopedia

CARVED BY ICE

ICE-AGE SCARS

For at least 2 million years, Earth has been in the
grip of ice ages. We are now living in a relatively warm
period, with ice only in the polar regions and in high
mountain ranges. But 22,000 years ago, much of
northern North America and northern Eurasia were
shrouded by ice sheets and glaciers. As the ice melted,
it left dramatic scars in the landscape, especially in the
rocky uplands. These include deep U-shaped valleys
and glacial lakes carved by glaciers, vast scree slopes of
frost-shattered rock, and heaps of rocky debris known
as moraines. In fact, nearly all the mountain landscapes
that are most admired today were shaped by ice.

AT A GLANCE
• LOCATION North America, Eurasia,

Patagonia, and New Zealand
• FORMATION Erosion by ice that has
since melted
• AGE More than 10,000 years old
• LARGEST GLACIAL FEATURES
The Great Lakes

STATS AND FACTS

GLACIAL ICE FRESH WATER
During the coldest
part of the most Today, 10% of About 70% of
Earth’s land is
Earth’s fresh
recent ice age, so covered with ice, water is stored
much water turned compared to 32% as glacial ice.
to continental ice that in the last ice age.
global sea levels fell by
up to 400 ft (120 m).
Thick ice sheets in the SEA LEVEL CANADA
Northern Hemisphere FROZEN WORLD
spread as far south as If all the glacial About 20,000
years ago, 97%
ice melted, the
Seattle and New York global sea level of Canada was
in the US, and Berlin would rise by entirely covered
in Germany. 230 ft (70 m). by ice.

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