The white spots in the oceans are islands where glaciers are found. Here's a map of where glaciers and icecaps exist in the world. White areas show glaciers and ice sheets around the world. A massive icecap can be found in Greenland, where practically the whole country is covered with ice (shouldn't it be called Whiteland)? The ice on Greenland approaches two miles (3.2 kilometers) in thickness in some places and is so heavy that some of the land has been compressed so much that it is way below sea level. Many lakes, such as the Great Lakes, and valleys have been carved out by ancient glaciers. In this picture you can see the bowl-shaped valley in a glacial valley in Wyoming where an ancient glacier forced its way through the landscape. You can imagine how a trillion-ton ice cube can rearrange the landscape as it slowly grinds its way overland. Glaciers have had a profound effect on the topography (lay of the land) in some areas, as in the northern U.S. Yosemite Valley is a classic U-shaped glacial valley in the Sierra Nevada, California.
COVERED BY WATER DRIFT PATCH
These glaciers can vary greatly in size, from a football-field sized patch to an ice patch a hundred miles (161 kilometers) long. These "rivers" of ice are tremendously heavy, and if they are on land that has a downhill slope the whole ice patch starts to slowly grind its way downhill. The weight of the accumulated snow compresses the fallen snow into ice.
When the snowfall in an area far exceeds the melting that occurs during summer, glaciers start to form.
In a way, glaciers are just frozen rivers of ice flowing downhill. Glaciers are important features in Earth's water cycle and affect the volume, variability, and water quality of runoff in areas where they occur. Almost 10 percent of the world's land mass is currently covered with glaciers and ice caps, mostly in places like Greenland and Antarctica. Even though you've maybe never seen a glacier or massive extents of ice, they are a big item when we talk about the world's water supply.
0 kommentar(er)
