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Deformation in a complex crustal-scale shear zone: Errabiddy Shear Zone, Western Australia
Geological Society, London, Special Publications, 2004Abstract Detailed mapping of four areas representing different geological units with varying formation histories within the crustal-scale Errabiddy Shear Zone shows an apparently simple temporal progression from foliation and mineral lineation development to folding and then to brittle deformation across the shear zone. However, in detail the
Occhipinti, Sandra, Reddy, Steven
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Formation and maintenance of shear zones
Geology, 2006The processes that initiate and maintain prograde ductile shear zones are not well understood. We have performed shear experiments (γ = 1 to 3) on a fine-grained (100– 150 μm) gneiss (59% quartz, 28% plagioclase, 13% aligned but not interconnected biotite) to determine the evolution of deformation mechanisms that produce dramatic strain weakening and ...
Caleb W. Holyoke, Jan Tullis
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On mylonites in ductile shear zones
Journal of Structural Geology, 1980Abstract In this contribution, shear zones are treated as zones of inhomogeneous deformation in which strain softening has occurred. The mylonites which form in ductile shear zones are the softened medium. The development of mylonite microstructures and fabrics are discussed from this point of view.
F.J. Humphreys +4 more
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Ductile Shearing in Attur Shear Zone and its Relation with Moyar Shear Zone, South India
Gondwana Research, 2000Abstract In the eastern part of southern Peninsular India, the charnockitic hills of the Madras block are cut across by the E-W trending Attur shear zone (ASZ) which is characterised by a thick (1 to 1.5 km) phyllonite zone, showing intense mylonitisation due to ductile shearing.
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Petroleum Geoscience, 2003
In deltaic and turbiditic deposits along passive margins, such as the Lower Congo basin on the West African margin, the main deformation is not induced by a regional tectonic stress field but by the increase of the sedimentary load leading to gravitational instabilities.
P. Victor +5 more
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In deltaic and turbiditic deposits along passive margins, such as the Lower Congo basin on the West African margin, the main deformation is not induced by a regional tectonic stress field but by the increase of the sedimentary load leading to gravitational instabilities.
P. Victor +5 more
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Maximum entropy and shear strain of shear zone
Mathematical Geology, 1992The principle of maximum entropy can be used to determine the shear strain in natural shear zones. When the margin of a shear zone is assumed, the principle leads to the truncated exponential distribution of the shear strain. Ifx is the distance remote from the shear zone center, which possesses the maximum shear strain, the shear strain γ (x) is given
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Tectonophysics, 1991
Abstract The geometric character of conjugate ductile shear zones has been defined from the structures developed in a undeformed granitoid corresponding to an homogeneous and isotropic material. In the plane perpendicular to the intersection line of conjugate zones (plane σ 1 σ 3 ) one notes that: (1) the principal direction of finite shortening ...
C. Lamouroux +2 more
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Abstract The geometric character of conjugate ductile shear zones has been defined from the structures developed in a undeformed granitoid corresponding to an homogeneous and isotropic material. In the plane perpendicular to the intersection line of conjugate zones (plane σ 1 σ 3 ) one notes that: (1) the principal direction of finite shortening ...
C. Lamouroux +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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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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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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