Transcript Glaciers
Exit Glacier Alaska Mrs. Degl 2006 1 That’s me climbing on glacial talus. What is glacial talus? Great question! It is a pile of debris at the end of a glacier, caused by melting ice. Mrs. Degl 2 Hiking on the Harding Icefield, which the Exit Glacier comes off of. Mrs. Degl 3 How do glaciers form?…………………… A glacier is a large mass of moving ice that flows slowly over the land. The glacier flows so slowly that you can’t even see it move. Glaciers are formed in high mountains or around the polar region. During the winter the snow piles up and the glacier grows. But during the summer some of the snow melts and evaporates. Year after year the snow piles up in layers. Mrs. Degl 4 As years pass the slab of ice gets bigger and grows thicker and becomes too big to stand still. The ice starts to move down the hill. When the ice moves it is called a glacier. During the summer some of the snow and ice melts but in some areas of the glacier the temperature doesn’t rise high enough to melt the snow and ice. Glaciers may also increase and decrease in size because of the changes in the climate around the glacier. For example, the ice sheet on Greenland is shrinking because of the rise in the temperature in the area. Mrs. Degl 5 Exit Glacier, the only area of Kenai Fjords National Park accessible by car, is one of thirty-five glaciers that flow off the Harding Icefield. The Icefield is the largest in North America, and it formed during the last ice age.. Mrs. Degl 6 Four major ice ages were recorded in North America. The last (Wisconsin) began about 70,000 years ago, and ended 10,000 years ago. During the last ice age approximately 97% of Canada was covered by ice. Mrs. Degl 7 Mrs. Degl 8 Glaciers Continental Glacier Large sheets of ice that cover whole continents. Valley/Alpine Glacier Slow-moving glaciers that are wedged between mountains. Mrs. Degl 9 Glacial Features Kettle lakes form as pieces of glaciers break off and melt. Mrs. Degl 10 New York has been covered with glaciers 4 times. These are photographs of Glacier Erratics. Erratics are boulders that were dropped by a glacier as it passed over the area. They are sure signs that the land was once covered by glaciers. There is an erratic in front of M.H.S (look above). Mrs. Degl 11 Parallel scratches form as small rocks stuck in the bottom of a glacier move over rocks in the ground and scratch them. These scratches are called striations. My picture from the Exit Glacier area shows the scratches. These scratches are found all over New York as well. Mrs. Degl 12 Large pieces of ice are breaking off glaciers each day as the ice melts due to increasing temperatures. Mrs. Degl 13 Thinking Ahead…………………………….. Let’s discuss a few things that could happen to the Earth if all of the glaciers melted. Click me for some ideas Mrs. Degl 14