Transpression

Sanderson, David J.; Marchini, W.R.D

doi:10.1016/0191-8141(84)90058-0

Cited by 903 publications

(463 citation statements)

References 14 publications

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“…In particular, a pure shear component, at different angles to the simple shear plane, has been shown to exist in many ductile shear zones (e.g. Sanderson and Marchini, 1984). While the above mentioned fundamental solutions are valid for any kind of far field flow they are somewhat difficult to evaluate (e.g.…”

Section: Far-field Vorticitymentioning

confidence: 99%

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Marques

Schmid

Andersen

2007

Journal of Structural Geology

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Rigid inclusion models have reached a stage where one should be able to use them to obtain quantitative values from ductile shear zones. We used natural data collected in three sites and combined analogue and theoretical modelling to assess vorticity, strain, nature of rigid inclusion/ matrix interface and confinement in the large-scale, ductile Nordfjord-Sogn Detachment Zone (NSDZ) of the Caledonides of western Norway. Our study shows that: (1) the observed shape preferred orientation (SPO) at higher structural levels of the NSDZ at Site 1, Gjervika, can be explained by simple shear (pure shear/simple shear ratio S r ¼ 0) associated with a slipping inclusion/matrix interface. (2) The observed SPO at deeper structural levels of the NSDZ at Site 2, near Sandane can be produced by simple shear associated with a significant amount of shortening across the shear zone (S r z 1), acting upon rigid inclusions in slipping contact with the enclosing matrix. The large scale extensional NSDZ under investigation shows evidence of strain partitioning: rocks vary from protomylonites to ultramylonites, and the simple shear and pure shear components are heterogeneously distributed. Therefore, we conclude that flow in the NSDZ was very heterogeneous both at the kilometre and the metre scale. However, the present study suggests that the amount of shortening across the shear plane throughout the NSDZ increases with depth, and the flattening component contributes to exhumation of the eclogite facies rocks in its footwall.

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Section: Far-field Vorticitymentioning

confidence: 99%

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Marques

Schmid

Andersen

2007

Journal of Structural Geology

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“…Models proposed here also favors previously envisaged late-stage shearing tectonic models (Morales 1993, Ebert & Hasui 1998), seemingly extendable to deeper levels (Boyer & Elliott 1982, Sanderson 1984, Sylvester 1988. Shear-related structures superposes the low-lying to medium-inclined thrust stacks and controls syn-to late-tectonic granitic bodies emplacement , Ebert & Hasui 1998, Mora et al 2014.…”

Section: Discussionmentioning

confidence: 72%

“…Complex geometries for both thrust-folding and shear systems observed in forward models, structural and metamorphism features are expected in a continuum crustal model for orogen evolution (Boyer & Elliott 1982, Sanderson 1984, Sylvester 1988. Syn-to late-orogenic granite bodies and massifs presents shallow roots along thrust and shear-related surfaces, confirming its relation to local magma generation and emplacement during orogeny late-stages , Sial et al 1999, Mora et al 2014.…”

Section: Gravity Domains (From a To H) Tectonic Frameworkmentioning

confidence: 69%

Geophysical perspective on the structural interference zone along the Neoproterozoic Brasília and Ribeira fold belts in West Gondwana

Motta

Morales²,

Filho³

2017

Braz. J. Geol.

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ABSTRACT:The Brasília and Ribeira fold belts have been established in south-southwestern São Francisco Craton during the Brasiliano-Pan African orogeny (0.9-0.5 Ga -Tonian to Cambrian), and played an important role in West Gondwana continent assembly. The region is given by a complex regional fold and thrust belt superposed by shearing during the orogeny late times, with superposing stress fields forming a structural interference zone. These thrust sheets encompasses assemblies from lower-to upper--crust from different major tectonic blocks (Paranapanema, São Francisco), and newly created metamorphic rocks. Re-evaluation of ground gravity datasets in a geologically constrained approach including seismology (CRUST1 model) and magnetic data (EMAG2 model) unveiled details on the deep-crust settings, and the overall geometry of the structural interference zone. The Simple Bouguer Anomaly map shows heterogeneous density distribution in the area, highlighting the presence of high-density, high metamorphic grade rocks along the Alterosa suture zone in the Socorro-Guaxupé Nappe, lying amid a series of metasedimentary thrust scales in a regional nappe system with important verticalization along regional shear zones. Forward gravity modeling favors interpretations of structural interference up North into Guaxupé Nappe. Comparison to geotectonic models shows similarities with modern accretionary belts, renewing the discussion. KEYWORDS: modeling; gravity; magnetics; thrust tectonics; shear zones. RESUMO: Os cinturões de dobramento Brasília e Ribeira foram estabelecidos na porção sul-sudoeste do Cráton São Francisco durante a orogenia

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“…L 4 was reoriented by D 5 strike-slip shear zones and, in most cases, would have rotated clockwise during D 5 dextral shearing. The initial maximum stretching direction in a transpressional shear zone ranges between 25Њ and 45Њ with respect to the shear planes (Sanderson and Marchini 1984;Tikoff and Peterson 1998), evolving to smaller values as deformation progresses. Such initial orientation constrains the original angle of L 4 to have been larger than the actual value for L 5 and sets the tectonic flow related to the D 4 basal extensional system at high angles to the trend of the chain.…”

Section: The Basal Detachment System Of the Allochthonous Complexesmentioning

confidence: 99%

Extensional Flow during Gravitational Collapse: A Tool for Setting Plate Convergence (Padrón Migmatitic Dome, Variscan Belt, NW Iberia)

Fernández

Catalán

Barreiro

et al. 2012

The Journal of Geology

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A B S T R A C TPlate convergence analysis in collisional orogens is usually based on the study of major contractional structures and strike-slip shear zones. Here we show how the structural analysis of extensional structures may report the regional or far stress field during relatively local, gravity-driven extensional collapse of a thickened continental crust and how this information may be used to constrain the broad vectors of plate convergence at that time. The Padró n migmatitic dome is a synconvergent extensional system developed in the axial zone of the Variscan belt exposed in the NW part of the Iberian Massif of Spain. This system affected the allochthonous and autochthonous sequences involved in Pangaea's assembly in Southern Europe. It includes three major extensional shear zones, which have been analyzed in detail to provide a wide ground data set for the discussion of the proposed model. The tectonic flow in the Padró n migmatitic dome and in other coeval structures is characterized by vectors ranging from parallel to oblique, in the latter case with a counterclockwise azimuth in relation to the trend of the orogenic belt. Our model suggests that the extensional collapse of the Variscan belt in NW Iberia would have developed if the convergence between Gondwana and Laurussia had not stopped and that it would have included a dextral component.

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Transpression

Cited by 903 publications

References 14 publications

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Applications of inclusion behaviour models to a major shear zone system: The Nordfjord-Sogn Detachment Zone in western Norway

Geophysical perspective on the structural interference zone along the Neoproterozoic Brasília and Ribeira fold belts in West Gondwana

Extensional Flow during Gravitational Collapse: A Tool for Setting Plate Convergence (Padrón Migmatitic Dome, Variscan Belt, NW Iberia)

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