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Schematic illustration of the two strike-slip fault types. The view is of the Earth's surface from above. In geology, the terms sinistral and dextral refer to the horizontal component of the movement of blocks on either side of a fault or the sense of movement within a shear zone. These are terms of relative direction, as the movement of the ...
A fault plane is the plane that represents the fracture surface of a fault. A fault trace or fault line is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. [3] [4] A fault zone is a cluster of parallel faults.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
Transform faults are closely related to transcurrent faults and are commonly confused. Both types of fault are strike-slip or side-to-side in movement; nevertheless, transform faults always end at a junction with another plate boundary, while transcurrent faults may die out without a junction with another fault.
Transtension is the state in which a rock mass or area of the Earth's crust experiences both extensive and transtensive shear.As such, transtensional regions are characterised by both extensional structures (normal faults, grabens) and wrench structures (strike-slip faults).
Rocks above the detachment fault form normal faults and, at the same time, shear in a "layer-parallel" motion. [11] This action creates a series of fault blocks, which are progressively tilted as the detachment fault progresses. [5] The fracturing of the fault blocks can occur in a similar time frame or develop progressively. [12]
When a strike-slip fault is offset along strike such as to create a gap e.g. a left-stepping bend on a sinistral fault, a zone of extension or transtension is generated. Such bends are known as releasing bends or extensional stepovers and often form pull-apart basins or rhombochasms.
Normal fault: Longmen Shan Fault: Sichuan, China: Thrust fault: Active: 2008 Sichuan (M8.0) Lost River Fault: Idaho, United States: Normal: Active: 1983 Borah Peak (M6.9) Lusatian Fault: Germany: Thrust fault: Macquarie Fault Zone >400: South Pacific Ocean: Fault (geology)#Strike-slip faults: Active: 1989 Maquarie Isl. (8.2), 2008 Macquarie ...