P.R. Cobbold

Université de Rennes

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Eduardo A. Rossello

Fundación Ciencias Exactas y Naturales

Denis Gapais

Géosciences Rennes

Olivier Galland

University of Oslo

Pierrick Roperch

Université de Rennes

Erwan Hallot

Centre National de la Recherche Scientifique

Jean de Brémond d’Ars

Centre National de la Recherche Scientifique

Helge Løseth

Equinor (United Kingdom)

Alain Zanella

Le Mans Université

Philippe Davy

Centre National de la Recherche Scientifique

César Arriagada

University of Chile

Cooperative Institutions

Centre National de la Recherche Scientifique

Université de Rennes

Géosciences Rennes

Institut de Recherche pour le Développement

Institut des Sciences de la Terre

Equinor (Norway)

Sorbonne Université

Petrobras (Brazil)

Imperial College London

University of Oslo

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Displacements, strains, and rotations within the Afar depression (Djibouti) from restoration in map view

Tectonics (1996)

Delphine Rouby T. Souriot Jean‐Pierre Brun P.R. Cobbold

Within the Afar depression (Djibouti) the stratiform basaltic lava flows (emplaced between 4 Ma and 1 Ma) cover the two thirds of the depression. Because of the desert climate, they are almost non eroded. The topography can then be used as a reference surface to measure the vertical offset of younger faults. Using a detailed map the southeastern part of the depression showing the fault pattern and the vertical offset on each fault (obtained from stereoparts of SPOT images), we have restored the topography in map view. We have computed the fields of finite displacement, rotation and strain. The field of horizontal displacements shows vectors trending to the NE on average. This direction is compatible with the displacement to the NE of the Arabian plate with reference to the African plate. In detail however, displacement vector trend from NNE‐SSW to NE‐SW. Major axes of strain ellipse trend NE‐SW suggesting that major faults (Nl20) are dominantely extensional. Strain intensities and magnitudes of block rotations are increasing from southwest to northeast of the restored area. Magnitudes of block rotations are very small compared with those obtained from paleomagnetic measurements. Therefore we computed a second restoration that covers a smaller area where the true vertical offset of the major faults taking into account the sedimentary fill of basins were avalaible. This second model gives rotation magnitudes in better agreement with paleomagnetic data but still underestimates. We discuss these results with the available kinematic models of the southeastern part of the depression.

Clockwise

10.1029/96tc00849

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Citations (19)

Structure, metamorphism an geochronology of the Arequipa Massif of coastal Peru

Journal of the Geological Society (1979)

R. SHACKLETON A. C. Ries M. P. Coward P.R. Cobbold

The Arequipa Massif, between the Andes and the Pacific, is an extensive pre-Devonian metamorphic complex. The sequence of deformations, metamorphisms and magmatism in this complex has been established. Mollendo, Atico and Marcona events are distinguished by structural and metamorphic methods and dated by Rb-Sr whole-rock isochrons, at about 1918, 440 and 392 Ma respectively. The Mollendo event led to partial melting, followed by granulite-facies metamorphism, in sediments buried to about 30 km. Further NW, sillimanite-bearing migmatites and staurolite-andalusite schists are thought to represent the same event. The tectonic trend is uncertain but the structures and metamorphism suggest a collision orogeny which probably pre-dated the Pacific Ocean. The early Caledonian Atico and Marcona events are associated with coast-parallel batholiths, amphibolite- to greenschist-facies metamorphism and penetrative deformations. The Atico and Marcona events are separated by the deposition of the Marcona Formation, which is therefore thought to be Lower Palaeozoic (between about 440 and 392 Ma). The early Caledonian deformations are attributed to a subduction zone near the present Pacific margin. There is no penetrative Hercynian or Andean deformation in the Arequipa Massif. Palaeomagnetic study of Jurassic andesites and dykes suggests that there has been no latitudinal motion of the Arequipa Massif relative to the Brazilian shield during the evolution of the Andes.

Geochronology

Massif

10.1144/gsjgs.136.2.0195

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Citations (111)

Buckling of an embedded layer in rubberlike materials: a critical comparison of theories

Tectonophysics (1982)

P.R. Cobbold

Biot number

10.1016/0040-1951(82)90139-1

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Geological evidence for fluid overpressure, hydraulic fracturing and strong heating during maturation and migration of hydrocarbons in Mesozoic rocks of the northern Neuquén Basin, Mendoza Province, Argentina

Journal of South American Earth Sciences (2015)

Alain Zanella P.R. Cobbold Gilles Ruffet Héctor A. Leanza

Anticline

Syncline

Bedding

Overpressure

Outcrop

Sill

10.1016/j.jsames.2015.06.006

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Citations (46)

Paleomagnetic evidence for Cenozoic block rotations in the Tadjik depression (Central Asia)

Journal of Geophysical Research Atmospheres (1994)

J. C. Thomas Annick Chauvin Denis Gapais Mikhail L. Bazhenov H. Perroud

This paper presents results of a paleomagnetic study of Oligo‐Miocene red beds of the Tadjik depression in Central Asia. We sampled about 530 cores at 69 sites and six localities across the depression and along the western border of the Pamirs. Samples were thermally demagnetized and high‐temperature components appear to predate folding of upper tertiary age. Throughout the depression, paleomagnetic inclinations are consistent with those observed on the stable Turan platform, at the western margin of the depression. However, they are shallower by about 30° than the inclination predicted from the reference apparent polar wander path. This appears to indicate a 23° difference in latitude, which is incompatible with paleogeographic reconstructions for the Tertiary. A sound interpretation of this anomaly would require a better‐constrained Tertiary paleomagnetic reference for Asia. Inside the Tadjik depression, paleomagnetic declinations are all significantly rotated, counterclockwise with respect to those measured on the Turan platform. The eastern part of the depression is a domain of large rotation (52°±13° to 46°±15°), whereas smaller amounts of rotation have occurred in the western part (27°±14° to 14°±15°). The similarity between Tertiary and Cretaceous data available for the area shows that rotations have occurred since the Miocene. Little or no paleomagnetic rotations are observed in the ranges bordering the northern and western parts of the depression. Paleomagnetic and structural data suggest that block rotations in the Tadjik depression are associated with indentation of the Pamirs into stable Asia. At a larger scale, observed rotations are compatible with a model of regional sinistral wrenching, along a strip running from the Gulf of Oman to Lake Baikal.

Clockwise

Neogene

Paleogene

Magnetic declination

Magnetostratigraphy

10.1029/94jb00901

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Citations (101)

Spatial integration of strains using finite elements

Journal of Structural Geology (1983)

P.R. Cobbold M.N. Percevault

Minification

10.1016/0191-8141(83)90018-4

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Citations (42)

Analogue models for the transpressional docking of volcanic arcs in the Western Pacific

Tectonophysics (1996)

Manuel Pubellier P.R. Cobbold

Convergent boundary

Volcanic arc

Continental Margin

Collision zone

continental collision

10.1016/0040-1951(95)00034-8

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Citations (41)

Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine

Geology (1982)

P. Tapponnier G. Peltzer A. Y. Le Dain Rolando Armijo P.R. Cobbold

Research Article| December 01, 1982 Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine P. Tapponnier; P. Tapponnier 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France Search for other works by this author on: GSW Google Scholar G. Peltzer; G. Peltzer 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France Search for other works by this author on: GSW Google Scholar A. Y. Le Dain; A. Y. Le Dain 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France Search for other works by this author on: GSW Google Scholar R. Armijo; R. Armijo 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France Search for other works by this author on: GSW Google Scholar P. Cobbold P. Cobbold 2Centre Armoricain d'Etude Structurale des Socles, Université de Rennes, 35042 Rennes, France Search for other works by this author on: GSW Google Scholar Author and Article Information P. Tapponnier 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France G. Peltzer 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France A. Y. Le Dain 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France R. Armijo 1Laboratoire de Physique et Mécanique des Matériax Terrestres, Institut de Physique du Globe, Université P. et M. Curie, 4 Place Jussieu, 75230 Paris, France P. Cobbold 2Centre Armoricain d'Etude Structurale des Socles, Université de Rennes, 35042 Rennes, France Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1982) 10 (12): 611–616. https://doi.org/10.1130/0091-7613(1982)10<611:PETIAN>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation P. Tapponnier, G. Peltzer, A. Y. Le Dain, R. Armijo, P. Cobbold; Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine. Geology 1982;; 10 (12): 611–616. doi: https://doi.org/10.1130/0091-7613(1982)10<611:PETIAN>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Plane indentation experiments on unilaterally confined blocks of plasticine help us to understand finite intracontinental deformation and the evolution of strike-slip faulting in eastern Asia. Several large left-lateral strike-slip faults may have been activated successively, essentially one at a time. The experiments suggest that the penetration of India into Asia has rotated (≈25°) and extruded (≈800 km) Indochina to the southeast along the then left-lateral Red River fault in the first 20 to 30 m.y. of the collision. This process can account for the opening of the South China Sea before late Miocene time. Extrusion tectonics then migrated north, activating the Altyn Tagh fault as a second major left-lateral fault and moving southern China hundreds of kilometres to the east. As this occurred, Indochina kept rotating clockwise (as much as 40°), but the sense of motion reversed on the Red River and other strike-slip faults in the south. Opening of the Mergui basin and Andaman Sea (up to the present) also appears to be a simple kinematic consequence of the extrusion. Recent rifts in northeastern China and Yunnan may be considered incipient analogs of the South China and Andaman Seas. Other Tertiary tectonic features such as the sedimentary basins of the Gulf of Thailand may be explained as collisional effects, if one uses our experiments as a guide. The experiments also suggest that a major left-lateral strike-slip fault and rift system will propagate across the Tien Shan, Mongolia, and Baikal to the Sea of Okhotsk. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Globe

Marie curie

Plasticine

10.1130/0091-7613(1982)10<611:petian>2.0.co;2

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Citations (2,682)

Lateral extrusion in the eastern Alps, Part 1: Boundary conditions and experiments scaled for gravity

Tectonics (1991)

Lothar Ratschbacher Olivier Merle Philippe Davy P.R. Cobbold

Lateral extrusion encompasses extensional collapse (gravitational spreading away from a topographic high in an orogenic belt) and tectonic escape (plane strain horizontal motion of wedges driven by forces applied to their boundaries). In the Eastern Alps it resulted from (1) an overall northerly compression (Apulia against Eurasia), (2) a strong foreland (Bohemian massif), (3) lack of constraint along a lateral boundary (Carpathian region), and (4) a previously thickened, gravitationally unstable, thermally weakened crust (Eastern Alpine orogenic belt). Six indentation experiments reproduce lateral extrusion at lithospheric scale. The models have two to four lithospheric layers, with a Mohr/Coulomb rheology for the upper and a viscous rheology for the lower crust. The lithosphere rests upon a low‐viscosity asthenosphere. A broad indenter, a narrow deformable area, and a weakly constrained eastern margin fullfill as closely as possible conditions in the Eastern Alps. Indentation produces both thickening in front of the indenter and escape of triangular wedges. Lateral variations in crustal thickness become attenuated by gravitational spreading. The overall fault pattern includes domains of reverse, strike‐slip, oblique normal, and pure normal faults. Strike‐slip faults in conjugate sets develop serially. The narrow width of the deformable area and the strength of the foreland determine the angles between the sets. Gravitational spreading produces a rhombohedral pattern of oblique and pure normal faults along the unconstrained margin. Opposite the unconstrained margin, the indenter front shows thrusts and folds intersecting with the conjugate strike‐slip sets. A triangular indenter favors spreading. High velocity of indentation favors escape. High confinement limits lateral motion, inhibits spreading, and favors thickening. Lateral extrusion in the Eastern Alps is best modeled by (1) a weak lateral confinement, (2) a broad and straight indenter, (3) a narrow width of the deformable area, and (4) a rigid foreland. Crustal thickening, lateral escape, and gravitational spreading all contribute to the overall deformation.

Lithospheric flexure

Asthenosphere

Massif

10.1029/90tc02622

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Citations (386)

El Bolsón Pagancillo (La Rioja, Argentina), Una Fosa Tectónica Constrictiva en un Ambiente Subandino y su Relación con el Lineamiento de Valle Fértil [PAPER IN SPANISH] El Bolsón Pagancillo (La Rioja, Argentina), a Rift Valley into a Constrictive Sub And

Eduardo A. Rossello Marcos E. Mozetic P.R. Cobbold Oscar R. López-Gamundí

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