Results 211 to 220 of about 309,304 (235)
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Late Hercynian shear zones in Sardinia
Tectonophysics, 1990Abstract In the past few years two main late Hercynian shear zones have been identified in Sardinia: the Mount Grighini shear zone in the centre of the island and the Posada Valley shear zone in the north. Both are dextral wrench shear zones, affecting the Hercynian basement during the Late Carboniferous, and characterized by a simple shear ...
Elter F. M. +2 more
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Journal of Structural Geology, 2005
Folds in ductile shear zones are common structures that have a variety of origins. These can be pre-existing folds that become modified or folds developed during the shearing event. Among the syn-shearing folds, a second subdivision is based on the relative age of the folded surface, which can be pre-existing or newly formed during the shearing event ...
Jordi Carreras +2 more
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Folds in ductile shear zones are common structures that have a variety of origins. These can be pre-existing folds that become modified or folds developed during the shearing event. Among the syn-shearing folds, a second subdivision is based on the relative age of the folded surface, which can be pre-existing or newly formed during the shearing event ...
Jordi Carreras +2 more
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Shear Zones and Mineralized Fissures [PDF]
, 1987 All researchers recognize the important implication of faulting for the geological setting of the Pechenga region. These were studied in most detail in the Pechenga ore field. According to Gorbunov et al. (1978), the geological structure of the Pechenga ore field was formed in five stages.
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2019
The Romeral shear zone marks the geological boundary between the physiographic Central and Western cordilleras of the Colombian Andes. It demarcates and encompasses the main locus of deformation associated with the amalgamation and geological-structural evolution of the Northern Andean region during the Meso-Cenozoic, although as an ancient plate ...
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The Romeral shear zone marks the geological boundary between the physiographic Central and Western cordilleras of the Colombian Andes. It demarcates and encompasses the main locus of deformation associated with the amalgamation and geological-structural evolution of the Northern Andean region during the Meso-Cenozoic, although as an ancient plate ...
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The Grenville Province as a shear zone
Nature, 1977PALAEOMAGNETIC and structural data on the Grenville Province in North America are best explained if the Grenvillian ‘orogeny’ was caused by right-lateral simple shear of the entire Province. Relative displacement of the edges of the belt is estimated at 200–300 km.
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Terminations of ductile shear zones
Tectonophysics, 1986Abstract We propose a plane strain model for ductile shear zone terminations in rocks that otherwise record no visible shear strain. This model may explain the strain distribution patterns in naturally occurring terminations of shear zone which show, in the XZ plane of finite strain, (1) a decrease in the area of finite strain and in strain ...
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Large shear zones with no relative displacement
Terra Nova, 2008AbstractIn the Oman ophiolite, the large scale Makhibiyah shear zone, in Wadi Tayin massif was generated with no or little relative motion between the two adjacent blocks, in contrast with what is reported from otherwise similar shear zones in deep crust and upper mantle. This shear zone is asymmetrical with, along one margin an asthenospheric mantle (∼
Nicolas, Adolphe, Boudier, Françoise
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Graphite and Shear Zone Evolution
2016Graphite is one of the most distinctive features of the Macraes deposit. Graphite occurs in schist host rocks as variably matured primary organic matter and as structurally-controlled hydrothermal precipitates. Hydrothermal graphite is particularly enriched in Macraes deposit, in micaceous shears.
Dave Craw, Doug MacKenzie
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Journal of Structural Geology, 1998
Abstract Although many ductile shear zones are supposed to have developed by approximately simple shear flow, some must have formed under different conditions. A few types of such ‘non-simple shear zones’ have been proposed in the literature such as transpression-, transtension- and stretching-shear zones. This paper presents a full three-dimensional
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Abstract Although many ductile shear zones are supposed to have developed by approximately simple shear flow, some must have formed under different conditions. A few types of such ‘non-simple shear zones’ have been proposed in the literature such as transpression-, transtension- and stretching-shear zones. This paper presents a full three-dimensional
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Fast shearing of pre-existing shear zones in soil
Géotechnique, 1996The paper presents results from a laboratory investigation into the influence of fast rates of displacement on the residual strength of soil. This influence was studied in the ring shear apparatus. Shear zones were formed by slow drained shearing and then tested at alternately fast and slow rates of displacement.
T. E. Tika +2 more
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