Glaciers

A glacier is a large, moving sheet of ice and snow.  Next to oceans, glaciers hold the most water on earth.  The polar areas are covered largely by glaciers and in warmer areas, glaciers cover the highest mountain tops.  Many other geologic features can also be formed by glaciers as well.  Glaciers can be found on every continent.  

Glaciers typically move very slowly.  However, there are short times when the glacier moves faster than its normal speed.  Glaciers move rocks and soil as they move across the land surface.  Because of their shape, weight and the rocks they carry, glaciers can leave behind new geologic features as they travel.  Moraines form when rocks and other debris pile up on the sides and ends of a glacier.  Valleys, in the shape of a "U" are forms as a glacier passes over the land surface.  The study of glaciers is one of the most interesting subjects in geology.