What is Transpression stress and Transtension stress?
Abstract: Transpression and transtension are strike-slip deformations that deviate from. simple shear because of a component of, respectively, shortening or extension orthogonal to the deformation zone.
What is a dextral strike-slip fault?
A strike-slip fault is a fault that moves laterally, or side to side. Faults that move to the right are called dextral, or right-lateral. Faults that move to the left are called sinistral, or left-lateral. A strike-slip fault can also be oblique, meaning it moves vertically as well as laterally.
What is Transpressional deformation?
In geology, transpression is a type of strike-slip deformation that deviates from simple shear because of a simultaneous component of shortening perpendicular to the fault plane. Transpression that occurs on a regional scale along plate boundaries is characterized by oblique convergence.
What is the meaning of Transtension?
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).
What causes Transpression along a transform boundary?
Transpression occurs where there is a component of compression in addition to the shearing motion. These forces build up around the area of the bend, where the opposing plates are restricted from sliding past each other. As the forces continue to build up, they create mountains in the restraining bend around the fault.
What is dextral system?
1. adj. [Geology] Pertaining to a strike-slip fault or right-lateral fault in which the block across the fault moves to the right. If it moves left, the relative motion is described as sinistral. Clockwise rotation or spiraling is also described as dextral.
What is a dextral shell?
Definition of dextral shell : a spiral gastropod shell the whorls of which turn from left to right.
What is Riedel shear?
The Riedel shears (also called R shears) are the small right-lateral faults which are gently inclined to the strike of the main fault. Their presence suggests overall right-lateral motion on the zone.
How do pull apart basins form?
Pull-apart basins form in extensional to transtensional environments along fault bends or between two adjacent left-lateral faults or two right-lateral faults. The step-over or bend in the fault must be the same direction as sense of motion on the fault otherwise the area will be subject to transpression.
