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Skip to content Study with The Open University. Search for free courses, interactives, videos and more! Free Learning from The Open University. Featured content. Free courses. All content. Speed and melt of glaciers Updated Tuesday, 27th February Copyright information. Publication details Originally published : Thursday, 20th July Last updated on : Tuesday, 27th February Be the first to post a comment Leave a comment.
Sign in or create your OpenLearn account to join the discussion. Feeds If you enjoyed this, why not follow a feed to find out when we have new things like it? Related content tags. Related content. Have a question? An example of such a glacier is the Berg Glacier on Mt. Robson Figure The Berg Glacier also loses mass by melting, especially at lower elevations. These diagrams represent a glacier with markers placed on its surface to determine the rate of ice motion over a one-year period.
The ice is flowing from left to right. See Appendix 3 for Exercise Figure An east to west cross section of the ice on Greenland is less than km long and up to 3 km high.
Skip to content Chapter 16 Glaciation. In the middle diagram, the leading edge of the glacier has advanced. Draw in the current position of the markers. In the lower diagram, the leading edge of the glacier has retreated. Previous: Next: Other factors that affect the velocity of a glacier include the roughness of the rock surface friction , the amount of meltwater, and the weight of the glacier.
Basal sliding and plastic flow. A valley glacier has various components of flow. First, the entire glacier moves as a single mass over the underlying rock surface. The pressure from the weight of the glacier generates a layer of water that helps the ice glacier move downslope. This process is called basal sliding. The central and upper portions of a glacier, as do those portions of a stream, flow more quickly than those near the bottom and sides, where friction between the ice and valley walls slows down the flow.
There are many types of moraines: Terminal or toehold — The advancing ice scrapes and grinds the bedrock boulders and gravel beneath it and pushes ahead of itself a ridge or terminal moraine of rock and earth.
Lateral — their rock material comes from the valley walls. Medial — When two lateral moraines combine, or a tributary glacier joins the main flow, they form a single medial moraine, which extends as a long, dark stripe down the middle of the glacier towards the snout. When medial moraines come close to one another near the terminus, a glacier may look multicolored or striped.
Medial moraines can create interesting swirls and loops. Ablation — an accumulation of melted-out rocks sometimes just sparse collections of glacial till.
End and Push — created near the margin of a glacier, at the terminus. Ground and Dump — glaciers often dump out their supply of rocks as they retreat. Moraines from tributaries. Barnard Glacier, Alaska, Looping medial moraines.
Photos by James Roush. Hubbard Glacier, Alaska. Photo by Alean. Glacier flour. Photo by Dr. Bruce Molnia, Alaska Geographic Society. Photo by Alaska Geographic Society. Stakes measuring glacier movement at the Bering Glacier in Alaska.
Photo by James Roush. Scientist measures the movement of the Bering Glacier in Alaska. How do Glaciers Move? Vocabulary Plus! Review Questions some of the answers may come from the vocabulary list What causes the glacier to be in motion?
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