Geological aspects of deformation in continental shear zones

Nicolas, Adolphe; Bouchez, Jean‐Luc; Blaise, J.; Poirier, Jean‐Paul

doi:10.1016/0040-1951(77)90017-8

Cited by 100 publications

(36 citation statements)

References 14 publications

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“…As a special geological dynamic-mechanical phenomenon occurring with the formation of a larger fault, penniform fractures are a group of secondary fractures produced with the formation of the primary fracture [25]. It happened to occur in our experiments that there are penniform fractures accompanying primary fracture in the compressive-loaded rock samples.…”

Section: Compressively Sheared Rockmentioning

confidence: 96%

Precursors for rock fracturing and failure—Part I: IRR image abnormalities

Liu

et al. 2006

International Journal of Rock Mechanics and Mining Sciences

129

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There are many precursors, including the abnormality of infrared radiation (IRR), for rock fracturing and failure. As the comprehensive effect of rock thermoelasticity and rock friction, the study of the IRR abnormality of loaded rock, as one of the important issues of remote sensing rock mechanics (RSRM), is facilitated by the fast development of IR remote sensing imaging technology. In view of energy input and consumption by the loading system, comprised of loader, rock and air, the mechanism of surface IRR from loaded rock is studied. The concepts that surface IRR is the comprehensive effect of a series of physical-mechanical processes inside loaded rock and that the thermoelastic effect and the frictional-thermal effect are two of the main mechanisms are presented here. Based on retrospective investigation of the fundamental experiments on RSRM during the past decade, it is concluded that there are two kinds of IRR abnormality as precursors of rock fracturing and failure: IRR image abnormality and IRR temperature curve abnormality. The spatial-temporal evolution of abnormal surface IRR images of loaded rock in a condition of uniaxial stress, compressive shear, biaxial stress, frictional slide and impact is systematically analyzed. The fact that large IRR can occur in the fracturing center of compressively loaded and shearing fractured strong and brittle rock is also revealed. Finally, the relation between rock stress and IRR temperature are studied based on thermomechanical coupling theory for solid materials. It is concluded that IRR image abnormalities are important precursors for rock fracturing and meaningful for the forecast of rockbursts and tectonic earthquakes. r

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Section: Compressively Sheared Rockmentioning

confidence: 96%

Precursors for rock fracturing and failure—Part I: IRR image abnormalities

Liu

et al. 2006

International Journal of Rock Mechanics and Mining Sciences

129

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“…Instead, the dominant foliation and stretching lineation effect the reduction of the tectonic and metamorphic profile in an extensional tectonic window. As already observed by Echtler and Malavieille (1990) and Nicholas et al (1977), sense of shear on the northern and southern flanks of the Zone Axiale, combined with transtensional faulting in the eastern termination of the structure indicate a dextral regime. The outline of the Zone Axiale defines a dextral pull-apart structure.…”

Section: Kinematic Frameworkmentioning

confidence: 63%

Hot metamorphic core complex in a cold foreland

Franke

Doublier

Klama

et al. 2010

Int J Earth Sci (Geol Rundsch)

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The Montagne Noire forms the southernmost part of the French Massif Central. Carboniferous flysch sediments and very low-grade metamorphic imprint testify to a very external position in the orogen. Sedimentation of synorogenic clastic sediments continued up to the Viséan/Namurian boundary (B320 Ma). Subsequently, the Palaeozoic sedimentary pile underwent recumbent folding and grossly southward thrusting. An extensional window exposes a hot core of Carboniferous HT/LP gneisses, migmatites and granites (Zone Axiale), which was uplifted from under the nappe pile. After the emplacement of the nappes on the Zone Axiale (Variscan D 1 ), all structural levels shared the same tectonic evolution: D 2 (extension and exhumation), D 3 (refolding) and post-D 3 dextral transtension. HT/LP-metamorphism in the crystalline rocks probably started before and continued after the emplacement of the nappes. Peak metamorphic temperatures were attained during a post-nappe thermal increment (M 2 ). M 2 occurred during ENE-directed bilateral extension, which exhumed the Zone Axiale and its frame as a ductile horst structure, flanked to the ENE by a Stephanian intra-montane basin. Map patterns and mesoscopic structures reveal that extension in ENE occurred simultaneously with NNW-oriented shortening. Combination of these D 2 effects defines a bulk prolate strain in a ''pinched pull-apart'' setting. Ductile D 2 deformation during M 2 dominates the structural record. In wide parts of the nappes on the southern flank of the Zone Axiale, D 1 is only represented by the inverted position of bedding (overturned limbs of recumbent D 1 folds) and by refolded D 1 folds. U-Pb monazite and zircon ages and K-Ar muscovite ages are in accord with Ar-Ar data from the literature. HT/LP metamorphism and granitoid intrusion commenced already at C330 Ma and continued until 297 Ma, and probably in a separate pulse in post-Stephanian time. Metamorphic ages older than c. 300 Ma are not compatible with the classical model of thermal relaxation after stacking, since they either pre-date or too closely post-date the end of flysch sedimentation. We therefore propose that migmatization and granite melt generation were independent from crustal thickening and caused, instead, by the repeated intrusion of melts into a crustal-scale strike-slip shear zone. Advective heating continued in a pull-apart setting whose activity outlasted the emplacement of the Variscan nappe pile. The shearzone model is confirmed by similar orogen-parallel extensional windows with HT/LP metamorphism and granitoid intrusion in neighbouring areas, whose location is independent from their position in the orogen. We propose that heat transfer from the mantle occurred in dextral strike-slip shear zones controlled by the westward

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“…Gèze, 1949 ;Schuiling, 1960;Nicolas et al, 1977;Beaud, 1985;Faure and Cottereau, 1988;Echtler and Malavieille, 1990;Maluski et al, 1991;Van Den Driessche and Brun, 1992;Brun and Van Den Driessche, 1994;Mattauer et al, 1996;Brunel and Lansigu, 1997;Matte et al, 1998;Demange et al 1999;Soula et al, 2001 and enclosed references). They can be grouped into three principal model types; however, due to incomplete arguments on the structure of the migmatites and Laouzas anatectic granite, none of them gives a satisfactory explanation of the dome formation.…”

Section: Emplacement Mechanisms Of the Montagne Noire Domementioning

confidence: 99%

“…Numerous studies have been carried out since more than half a century in order to decipher the doming processes and the relationships with the regional tectonics (e.g. Gèze, 1949;Schuiling, 1960;Nicolas et al, 1977;Beaud, 1985;Faure and Cottereau, 1988;Echtler and Malavieille, 1990;Maluski et al, 1991;Van Den Driessche and Brun, 1992;Brun and Van Den Driessche, 1994;Mattauer et al, 1996;Brunel and Lansigu, 1997;Matte et al, 1998;Demange et al 1999;Soula et al, 2001 and enclosed references; see Discussion section below for details).…”

Section: Introductionmentioning

confidence: 99%