Transcript Slide 1
A large mass of moving ice and snow Valley/alpine Alps in Europe Rockies Himalayas Andes Continental Greenland Antarctica CONTINENTAL ICE SHEETS 3. Valley Glaciers and Erosion a. Movement of a valley glacier- the center movesfaster __________ than the sides. Lateral Medial Ground (Terminal) b. Moraine- Unsorted rock material carried and deposited by a glacier Lateral 1.______________ moraine- unsorted rock on the glacier along the valley walls Medial 2. ______________ moraine- unsorted rock on the glacier in the central region resulting from the merging of two smaller valley glaciers. 3. Ground ______________ moraine- unsorted rock trapped at the bottom of the glacier. Terminal Retreat Ablation Advance accumulation River Glacier U Glaciers carved this broad U-shaped valley in the Rocky Mountains of Montana. 8 4. Ice Age Continental Glaciers In the geologic past, a much colder climate resulted in ice sheets covering much of Earth’s surface. 4 There is evidence of at least ____ major ice ages during the last 2 million years. Interglacial periods a. The time period between ice ages is called _______________. 11,000 b. The most recent ice age ended only about ____________ years ago. The average global temperatures over the past 1000,000 years. 11 11 Wisconsin illinoian Kansan Nebraskan NOVA Science Now Glacier Video (Click on the link) http://www.pbs.org/wgbh/nova/sciencenow/3210/03.html http://environment.nationalgeographic.com/environment/globalwarming/extreme-ice-survey-article.html DRUMLIN- A long, narrow hill composed of glacial till, which was shaped by moving ice. In New York, drumlins are steep at the north end and trail off to the south. Drumlins Erratic: A large rock or boulder moved by a glacier. Some erratics differ in rock type from the bedrock below them. Esker- A sinuous (winding ridge) deposited by a stream in a tunnel under a glacier. Kame- A small hill of sediment deposited by a stream, often at the edge of glacier. This process is similar to the formation of a delta where a stream enters calm water. -Moraine- An elongated and irregular pile of unsorted till deposited by moving ice, usually at the side or at the end of a glacier -Ground Moraine Terminal Moraine The north shore of Long Island has bluffs of glacial till in the Harbor Hill Moraine. The transported rocks of diverse types settle onto the beach. 24 The sandy beaches along the south shore are composed of sorted outwash sediment. 25 Outwash- Sediments carried away from a glacier by meltwater. Outwash is usually stratified (layered) and sorted NORTH South Shore of Long Island Till- An immature soil, with little organic material, composed of unsorted sediment that has been moved into place by a glacier. Glacial till sediment, in some places hundreds of feet thick, covers most of New York State. 28 Loess Glacial till Glacial outwash exposed in beach cliff at Caumsett State Park, Lloyd Neck, Long Island Polish- A bedrock surface smoothed by glacial abrasion. If fresh, it may reflect light Striations- Scratches on bedrock formed when a glacier dragged embedded rocks over a bedrock surface. Grooves- Long channels or furrows carved by rocks dragged under a moving glacier Whaleback- A rock knob shaped and plucked by moving ice. The sharper, plucked end is usually on the end to which the glacier advanced. (These are also known by their French name roche moutonnee scattered V-shaped by RIVER U-shaped by GLACIER