Transtensional Tectonics on:
[Wikipedia]
[Google]
[Amazon]
Transtension is the state in which a rock mass or area of the Earth's crust experiences both ''extensive'' and ''transtensive''
''Releasing bends'' are transtensional structures that form where the orientation of a strike-slip fault becomes oblique to the regional slip vector causing local extension (such as a right stepping bend on a right-lateral fault). They also form where two segments of a strike-slip fault overlap, and the relay zone between the segments experiences transtension. Releasing bends often form negative flower structures or
shear
Shear may refer to:
Textile production
*Animal shearing, the collection of wool from various species
**Sheep shearing
*The removal of nap during wool cloth production
Science and technology Engineering
*Shear strength (soil), the shear strength ...
. As such, transtensional regions are characterised by both extensional structures (normal faults Normal(s) or The Normal(s) may refer to:
Film and television
* Normal (2003 film), ''Normal'' (2003 film), starring Jessica Lange and Tom Wilkinson
* Normal (2007 film), ''Normal'' (2007 film), starring Carrie-Anne Moss, Kevin Zegers, Callum Keit ...
, graben
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults.
Etymology
''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...
s) and wrench structures (strike-slip fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
s). In general, many tectonic regimes that were previously defined as simple strike-slip shear zones are actually transtensional. It is unlikely that a deforming body will experience 'pure' extension or 'pure' strike-slip.
Transtensional shear zones are characterized by the co-existence of different structures, related to both strike-slip shear and extension. End member structures include pure strike-slip faults and purely extensional ("normal") dip-slip faults. Faults which have components of both (termed 'oblique' slip faults) are abundant.
Releasing bend
''Releasing bends'' are transtensional structures that form where the orientation of a strike-slip fault becomes oblique to the regional slip vector causing local extension (such as a right stepping bend on a right-lateral fault). They also form where two segments of a strike-slip fault overlap, and the relay zone between the segments experiences transtension. Releasing bends often form negative flower structures or pull-apart basin
In geology, a basin is a region where subsidence generates accommodation space for the deposition of sediments. A pull-apart basin is a structural basin where two overlapping (en echelon) strike-slip faults or a fault bend creates an area of cru ...
s. Geologists may also refer to a releasing bend as a right bend.
Transtensional regions
*Dead Sea
The Dead Sea ( he, יַם הַמֶּלַח, ''Yam hamMelaḥ''; ar, اَلْبَحْرُ الْمَيْتُ, ''Āl-Baḥrū l-Maytū''), also known by other names, is a salt lake bordered by Jordan to the east and Israel and the West Bank ...
Kearey, Philip and Frederick J. Vine, ''Global Tectonics,'' Blackwell Science, 2nd ed., 1996, pp. 131-133
* Salton Sea
* Sea of Marmara on the North Anatolian Fault
* Vienna Basin Royden, Leigh H., The Vienna Basin: a Thin-Skinned Pull-Apart Basin ''in'' N. Christie-Blick and K.T. Biddle (eds.), ''Strike-Slip Deformation, Basin Formation, and Sedimentation''. SEPM Special Publications, 37.
See also
*Pull-apart basin
In geology, a basin is a region where subsidence generates accommodation space for the deposition of sediments. A pull-apart basin is a structural basin where two overlapping (en echelon) strike-slip faults or a fault bend creates an area of cru ...
* Rift
* Strike-slip tectonics
* Structural geology
Structural geology is the study of the three-dimensional distribution of rock units with respect to their deformational histories. The primary goal of structural geology is to use measurements of present-day rock geometries to uncover informatio ...
* Transpression
References
Structural geology {{tectonics-stub