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Please help improve this article by expanding it. Further information might be found on the talk page. (October 2009) |
Fault-block landforms (mountains, hills, ridges, etc.) are formed when large areas of bedrock are widely broken up by faults creating large vertical displacements of continental crust.
Vertical motion of the resulting blocks, sometimes accompanied by tilting, can then lead to high escarpments. These mountains are formed by the Earth's crust being stretched and extended by tensional forces. Fault block mountains commonly accompany rifting, another indicator of tensional tectonic forces.
The uplifted blocks are called block mountains or horsts. The intervening dropped blocks are termed graben: these can be small or form extensive rift valley systems. This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America, in south-central New England, and the Rhine valley. These areas often occur when the regional stress is extensional and the crust is thinned.
Two types of block mountains are lifted and tilted. Tilted type block mountains have one gently sloping side and one steep side with an exposed scarp, and are common in the Basin and Range region of the western United States. Level blocks lead to the horst and graben terrain seen in northern Europe. Lifted type block mountains have two steep sides exposing both sides scarps.
See also
References
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This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. Please improve this article by introducing more precise citations where appropriate. (April 2009) |
- Plummer, Charles, David McGeary, and Diane Carlson. Physical Geology 8th ed. McGraw-Hill, Boston, 1999.
- Monroe, James S., and Reed Wicander. The Changing Earth: Exploring Geology and Evolution. 2nd educational Belmont: Wadsworth Publishing Company, 1997. ISBN 0-314-09577-2 (pp. 234,-8)
External links
- http://www.universetoday.com/guide-to-space/earth/fault-block-mountains/
- http://science.jrank.org/pages/2667/Fault-Mountain-building-by-small-movements-along-faults.html Fault - Mountain-building By Small Movements Along Faults
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