Fault-block mountain

Fault block formation in the Teton Range

The Hanging Hills of Connecticut (Metacomet Ridge range); upfaulting (horst) visible from right to left.

Fault-block geology

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.

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.

Notable Examples

• The Great Basin Ranges of (USA)
• The Vosges of (France)
• The Black Forest of (Germany)
• The Vindhyas and Satpuras of (India)
• The Rhine river flows through the graben between the two horsts, the Vosges and Black Forest.
• The Death Valley of California and the Great Rift Valley of Africa are well known rift valley systems.

See also

• List of mountain types
• Mountain
• Plate tectonics
• Orogeny
• Mountain building

References

• 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