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 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; 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 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