Presentation on theme: "Glaciers How are Glaciers and Long Island related?"— Presentation transcript:
Glaciers How are Glaciers and Long Island related?
Glaciers Snowfall exceeds melting. High altitudes and polar regions. Gravity moves mass downhill. Firn = very dense snow layer.
Continental Glaciers Ice sheets that cover continents. Kilometers thick. Only 2 exist: - Greenland and Antarctica
Valley Glaciers Begins in a cirque = bowl-shaped basin at mountaintop. Crevasses = cracks in the glacier.
Erosion U-shaped Valleys Cirques, Aretes and Horns. Hanging Valleys - from tributary
Erosion Striations = parallel scratches on bedrock... from rocks on bottom of glacier Polish = fine material rubs rock smooth.
Deposition Moraines - Unsorted pile of debris = till Erratics = large isolated boulders. Drumlins = long, low mounds of till with teardrop shape. Outwash Plain (sorted) = sediments that are washed out in front of glacier.