Detachment fault

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View from Wheeler Peak, Snake Range, Nevada, is one of the tallest peaks within the Great Basin, and was formed by detachment faulting.

Detachment faulting is associated with large-scale extensional tectonics. Detachment faults often have very large displacements (tens of km) and juxtapose unmetamorphosed hanging walls against medium to high-grade metamorphic footwalls that are called metamorphic core complexes. They are thought to have formed as either initially low-angle structures or by the rotation of initially high-angle normal faults modified also by the isostatic effects of tectonic denudation.

Seismic Detachments

Examples of detachment faulting include:

  • The Snake Range detachment system of the Basin and Range Province of western North America which was active during the Miocene
  • The Nordfjord-Sogn Detachment of western Norway active during the Devonian Period [1]
  • The Whipple detachment in southeastern California [2]
Seismic Detachment and Ramp

Detachment faults have been found on the sea floor close to divergent plate boundaries characterised by a limited supply of upwelling magma. These detachment faults are associated with the development of oceanic core complex structures.

References

  1. ↑ Fossen H. (1992). The role of extensional tectonics in the Caledonides of South Norway. Journal of Structural Geology, 14:1033–1046.
  2. ↑ Davis GA. (1988). Rapid upward transport of mid-crustal mylonitic gneisses in the footwall of a Miocene detachment fault, Whipple Mountains, southeastern California. Geologische Rundschau, 77/1:191–209.

George H Davis, Stephen J Reynolds, (1996), Structural Geology of Rocks and Regions, 2nd Edition, John Wiley and Sons Inc. ISBN 0-471-52621-5.

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