Within-plate zones of concentrated deformation: Tectonic structure and evolution

Leonov, M. G.

doi:10.1134/s0016852112060052

Cited by 28 publications

(22 citation statements)

References 6 publications

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“…All tectonic domains forming the Mongolian CAOB were affected by pronounced N‐S Permo‐Triassic shortening that resulted in the formation of subvertical E‐W trending high‐strain zones separated by weakly deformed domains [ Lehmann et al , ; Leonov , ; Guy et al , ]. The high‐strain zones are characterized by upright folds, subvertical cleavage, and the steepening of lithological units [ Guy et al , ].…”

Section: Geological Setting and Geophysical Backgroundmentioning

confidence: 99%

“…The complete Bouguer gravity anomalies of the profile A‐A′ range from approximately −240 mGal in the north to approximately −180 mGal in the south and are marked by five intermediate‐wavelength and several secondary short‐wavelength anomalies which can be better distinguished using the isostatic residual anomalies (Figure a). The upper and middle crusts are modelled as laterally variable vertical density units corresponding to the regional distribution of high‐strain (correlating with intermediate wavelength gravity highs) and low‐strain zones delineated at the surface [ Lehmann et al , ; Leonov , ; Guy et al , ]. The compositions of the high‐strain zones vary from Upper Riphean volcanic rocks through Ordovician granodiorites to Lower Carboniferous sediments.…”

Section: Geophysical Characterization Of the Lower Crustmentioning

confidence: 99%

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Geophysical and geochemical nature of relaminated arc‐derived lower crust underneath oceanic domain in southern Mongolia

et al. 2015

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The Central Asian Orogenic Belt (CAOB) in southern Mongolia consists of E-W trendingNeoproterozoic cratons and Silurian-Devonian oceanic tectonic zones. Previous study revealed that the Early Paleozoic accretionary wedge and the oceanic tectonic zone are underlain by a layer giving a homogeneous gravity signal. Forward gravity modelling suggests that this layer is not formed of high-density material typical of lower oceanic crust but is composed of low-to intermediate-density rocks resembling continental crust. The nature of this lower crust is constrained by the whole-rock geochemistry and zircon Hf isotopic signature of abundant Late Carboniferous high-K calc-alkaline and Early Permian A-type granitoids intruding the two Early Paleozoic domains. It is possible to explain the genesis of these granitoids by anatexis of juvenile, metaigneous (tonalitic-gabbroic) rocks of Late Cambrian age, the source of which is presumed to lie in the "Khantaishir" arc (520-495 Ma) further north. In order to test this hypothesis, the likely modal composition and density of Khantaishir arc-like protoliths are thermodynamically modelled at granulite-and higher amphibolite-facies conditions. It is shown that the current average density of the lower crust inferred by gravity modelling (2730 ± 20 kg/m 3 ) matches best metamorphosed leucotonalite to diorite. Based on these results, it is now proposed that Mongolian CAOB has an architecture in which the accretionary wedge and oceanic upper crust is underlain by allochthonous lower crust that originated in a Cambrian arc. A tectonic model explaining relamination of allochthonous felsic to intermediate lower crust beneath mafic upper crust is proposed.

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Section: Geological Setting and Geophysical Backgroundmentioning

confidence: 99%

Section: Geophysical Characterization Of the Lower Crustmentioning

confidence: 99%

Geophysical and geochemical nature of relaminated arc‐derived lower crust underneath oceanic domain in southern Mongolia

et al. 2015

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“…The development of these struc tures is a common property of many strike slip zones, which is substantiated by numerous natural and tec tonophysical models [12,16,17,25,31,32] (Fig. 12g).…”

Section: The Results Of Studies and Tectonic Morelsmentioning

confidence: 82%

Structure and evolution of the Sura-Kama strike-slip zone in the Cenozoic (the Volga-Ural anteclise of the East European Platform)

Kolodyazhnyi

2015

Geotecton.

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The Sura-Kama zone (SKZ) complicates the central area of the Volga-Ural anteclise and extends sublaterally from the Sura River basin towards the Kama River at a distance of 700-750 km. Based on the analysis of geological-geophysical data and structural studies, a model for the tectonic structure and the evolution of the SKZ is developed. This is a deep tectonic fault that shows the features of long-term polystage development. During the latest Cimmerian-Alpine period of tectonic reactivation, the SKZ rep resented a zone of strike slip and consecutive manifestation of early transpressional right lateral strike slip dislocations that changed to left lateral strike slip displacements under transtension settings as a result of kinematic inversion. Features of the heterogeneous structure of the SKZ are revealed. The segments formed by the system of strike slip duplexes are alternated along the strike by the principle of rotation-fold and "domino" structures. The particular models of evolution of these segments are proposed by the examples of the widely known Karlin, Tetyushin, and Lower Kama dislocations. It is assumed that kinematic inversion and compression-decompression phenomena on the flanks of the SKZ, as well as the tectonic environments in the area of its dynamic influence were highly important for the development of the processes of migration and redistribution of hydrocarbon components.

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“…В геологической литературе большое внимание уделено описанию узких линейных зон, которые, пронизывая земную кору на разную глубину, характеризуются очень сложной внутренней тектонической структурой и интенсивной вещественной переработкой горных масс, существенно более интенсивной, чем прилегающие к ним комплексы пород [Azhgirey, 1960;Bachmanov et al, 2008;Leonov, 2012b;2013a;Morozov, 1999Morozov, , 2002Morozov, Geptner, 1997;Morozov, Talitskii, 2006;Rastsvetaev, 2002;Timurziev, 2006Timurziev, , 2009Timurziev, , 2010Chikov, 2011;Chikov, Lin, 1995;Chikov et al, 2008;Alvarez, Maurin, 1991;Chemenda et al, 2016;Cunningham, 2010;Harland, 1971;Sylvester, 1988]. Подобные структуры описаны как зоны смятия или зоны концентрации деформаций [Azhgirey, 1960], линеаментные деформационнометаморфические зоны [Chikov, 2011], зоны концентрации сдвиговых деформаций [Rastsvetaev, 1973], структуры горизонтального сдвига [Timurziev, 2014] и пр.…”

Section: Introductionunclassified

Zones of concentrated deformation (flower structures): field observations and modeling data

Leonov

Морозов

Стефанов

et al. 2018

Geodin. tektonofiz.

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Our study was focused on narrow linear zones that penetrate to different depths the crust and have complex infrastructure. Rocks in such zones are more intensively tectonically altered in comparison with the background. ‘Flower structures’ and ‘zones of concentrated deformation’ (ZCD) are the terms to describe these zones. The field study results combined with the data of tectonophysical and computational modeling data and supplemented by the literature analysis gave grounds for the following conclusions. In the experiments, as well as in nature, ZCDs show similar and, in some cases, identical morphological and infrastructural features and have similar stages of their evolution. A ZCD is mainly a reflection of the transpression setting. Its formation is accompanied by 3D plastic shear flow of matter and dilatancy of the deformed volume. A ZCD may be associated with the development of the ‘basement – cover’ system. It may also occur due to the intra-cover tectogenesis that does not influence the basement. Locations of ZCDs are spatially regular and predetermine the tectonic divisibility of the crust and lithosphere.

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Within-plate zones of concentrated deformation: Tectonic structure and evolution

Cited by 28 publications

References 6 publications

Geophysical and geochemical nature of relaminated arc‐derived lower crust underneath oceanic domain in southern Mongolia

Geophysical and geochemical nature of relaminated arc‐derived lower crust underneath oceanic domain in southern Mongolia

Structure and evolution of the Sura-Kama strike-slip zone in the Cenozoic (the Volga-Ural anteclise of the East European Platform)

Zones of concentrated deformation (flower structures): field observations and modeling data

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