Search results
Results from the WOW.Com Content Network
Tilted block faulting, also called rotational block faulting, is a mode of structural evolution in extensional tectonic events, a result of tectonic plates stretching apart. [ 1 ] [ 2 ] When the upper lithospheric crust experiences extensional pressures, the brittle crust fractures, creating detachment faults . [ 3 ]
Fault-block mountain of the tilted type. [16] Sierra Nevada Mountains (formed by delamination) as seen from the International Space Station. When a fault block is raised or tilted, a block mountain can result. [17] Higher blocks are called horsts, and troughs are called grabens. A spreading apart of the surface causes tensional forces.
Lifted fault-block geology Tilted fault-block formation in the Teton Range. Fault-block mountains often result from rifting, an indicator of extensional tectonics. These can be small or form extensive rift valley systems, such as the East African Rift zone. Death Valley in California is a smaller example.
With crustal extension, a series of normal faults which occur in groups, form in close proximity and dipping in opposite directions. [4] As the crust extends it fractures in series of fault planes, some blocks sink down due to gravity, creating long linear valleys or basins also known as grabens, while the blocks remaining up or uplifted produce mountains or ranges, also known as horsts.
The Basin and Range Province in the western United States is an extensive region of alternating valleys and ridges caused by horst and graben as well as tilted block faulting. [ 1 ] The Condroz and Ardennes regions of Wallonia are good examples of a succession of horst and graben.
These normal faults, in this view, are steep near the surface but become low angle at depth; the mountain blocks rotated as they slid to produce the tilted mountains seen today. [17] Total movement of the Pamamint block between the Garlock and Furnace Creek Faults is 50 miles (80 km) to the northwest, giving birth to Death Valley in the process ...
The Rwenzori Mountains in the East African Rift are an upthrown fault block, and are the highest non-volcanic, non-orogenic mountains in the world. [13] [14] The Vosges Mountains in France were formed by isostatic uplift in response to the opening of the Rhine Graben, a major extensional basin. [15]
Though this surface is typically a plane, differential erosion of the tilted strata of the Unkar Group left resistant beds of the upper layer Cardenas Basalt and the middle layer Shinumo Quartzite as ancient hills, called monadnocks. These ancient hills, which are ridges formed by block faulting, are up to 240 m (790 ft) tall.