PPT-Glaciers Glacial Ice

Once glacial ice exceeds a thickness of about 150 feet the weight of the overlying ice causes the base of the glacier to become plastic and flow like a very viscous liquid While the bottom ice responds as a plastic solid the surface ice is very brittle However from the surface down to the top of the plastic portion of the glacier the ice experiences a decrease in . Glacial Ice. . Once . glacial ice exceeds a thickness of about 150 feet, the weight of the overlying ice causes . the . base of . the glacier . to become plastic and flow like a very viscous liquid. While the bottom ice responds as a plastic solid, the surface ice is very brittle. However, from the surface down to the top of the plastic portion of the glacier, the ice experiences a decrease in . Glacial Erosion. As glaciers travel over land, glacial ice can erode the underlying bedrock.. This erosion can happen by:. Plucking. A. brasion. Plucking. This occurs when melt water at the base of the glacier freezes in cracks and fractures the underlying bedrock.. Chapter 3: Changing Climates. The Big Freeze. A cooling trend began in the Cretaceous Period and continued throughout the Tertiary Period. By the end of the Tertiary Period (1.7 . mya. ) the climate became so cold that snow began o accumulate year after year in the Polar regions. Deposition:. AIM:. Erosional and Depositional systems. Do Now: In your notebooks…. 1) Define the two terms below in your own words.. 2) Explain how the two terms work together.. The movement/transport of material from one place to another. POWER POINT ON GLACIERS. U.RAVI RAJA . I . B.Sc. MPG. GLACIAL ACTION . Introduction. Ms. Martel. What Is A Glacier?. About 75% of Earth’s fresh water is frozen in glaciers.. A glacier is a large mass of compacted snow and ice that moves under the force of gravity.. Glaciers help to carve Earth’s landscapes as it erodes geological features in one place and then re-deposits the material elsewhere. . 5.7B. Thinking About Glaciers. Glaciers cover about one-tenth of the Earth’s surface. Most of the fresh water found on the Earth is frozen in glaciers.. Glaciers move very slowly and can cause very slow changes to the Earth’s surface.. Section 1: Glaciers – Moving Ice. Section 2: Glacial Erosion and Deposition. Section 3: Ice Ages. Section 1: Glaciers – Moving Ice. . N. atural . forces compact snow to make a large mass of moving ice called a . More winter snowfall than summer melt. Glacier formation is similar to sedimentary rock formation. Types of Glaciers. Valley glaciers or alpine glaciation. Ice sheets or continental glaciation. Glaciers of the world. Glacier – thick ice mass that forms over hundreds or thousands of years.. 15, 000 years ago > 30 % coverage - Today 10 % coverage. Valley Glaciers. Ice Sheets. Types of Glaciers. Valley Glaciers. Glaciers. Geologists define a . glacier. as any large mass of ice that moves slowly over land.. There are two types of glaciers:. Continental glaciers. Valley glaciers. Continental Glaciers. A . continental glacier. B. Landforms : an accumulation of till deposited by direct glacial action. Ground moraines are relatively level to gently rolling and are formed by the deposition of accumulated material beneath the Glacier. persistent . body of dense ice that is constantly moving under its own . weight.. It . forms where the accumulation of snow exceeds its ablation (melting and sublimation) over many . years.. Glacial transport . The image to the right shows the different ways in which material can be transported. Material that has been carried and deposited by the glacier is called moraine Different types of moraine .