Glaciers Chapter 3 Section 4
Standards • S 6.2a Surface water flow, glaciers, wind, and ocean waves have all been and continue to be active throughout California and the rest of the world in shaping landscapes.
Vocabulary • Glacier • Continental glacier • Ice age • Valley glacier
Plucking • Till • Moraine • Kettle
How Glaciers form and Move • 2 types of glaciers. • Continental glaciers – covers most of a continent or large island. • Valley glaciers- long, narrow glacier that forms when snow and ice build up. • Glaciers have been found in Antarctica and Greenland. • They flow in all directions
Ice Ages have occurred and have covered large parts of the Earth’s surface. • Glaciers will advance, retreat, or melt back. • Glaciers can only form in an area where more snow falls than melts. Gravity will begin to pull down the glacier. • They move a few centimeters a day.
2 processes that glaciers erode the land are plunking and abrasion • Plunking- as it moves across the land, it picks up rocks. It can even move large boulders. • Abrasion: gouges and scratches the bedrock. • A U shaped valley will be created that demonstrates that a glacier once covered the area.
When a glacier melts, it deposits the sediment it eroded from the land, creating various landforms. • If the sediment has been deposited directly on the surface it is called till. • The till deposited on the edges of a glacier forms a ridge called a moraine. • Terminal Moraine: the ridge of till at the farthest point reached by a glacier.
A kettle is a small depression that forms when a chunk of ice is left is left in glacial till.
Checking for Understanding • What is a continental glacier? • What is a valley glacier? • How does a glacier form? • How does a glacier move?
Guided PracticeIndependent Practice • Guided Practice: page 66-67 # 1-22 • Independent Practice: Glacier Worksheet