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A. G. Vladimirov A. E. Izokh G. V. Polyakov G. A. Babin A. S. Mekhonoshin N. N. Kruk V. V. Khlestov S. V. Khromykh A. V. Travin D. S. Yudin R. A. Shelepaev I. V. Karmysheva E. I. Mikheev 《Petrology》2013,21(2):158-180
One of the problems faced by researchers when paleogeodynamic reconstructions are carried out for deeply eroded orogenic terranes is the limited usage of geological and isotopic geochemical data on volcanic associations. The utilization of information on gabbroids and granitoids considered separately also fails to resolve this problem. The convergence of features of arc, collisional, and within-plate magmatic processes leads the researcher to search for indicator plutonic associations, such as paired gabbrogranite intrusive series. The latter were distinguished using geoinformation databases (including those compiled by the authors of this paper), which were composed for the Early Caledonides in the Altai-Sayan folded area and adjacent territories. This makes it possible to characterize mantle-crustal magmatism in suprasubductional and collisional environments and the conditions under which these geodynamic regimes (plate- and plume-tectonic factors) interact. This paper presents estimates of the composition of the parental basic magmas, distinctive features of their differentiation, and the compositional specifics of the accompanying extensive granite-forming processes. The example of the Altai-Sayan folded area and adjacent territories is employed to correlate the composition of the basic-ultrabasic and granitoid magmas and, on this basis, distinguish (a) differentiated gabbro-tonalite-plagiogranite intrusive series corresponding to accretionary-collisional geodynamic environments, and (b) gabbro-monzonite-granosyenite-potassic granite intrusive series, which were produced when the accretionary-collisional system was affected by a plume. 相似文献
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S.V. Khromykh A.G. Vladimirov A.E. Izokh A.V. Travin I.R. Prokop’ev E. Azimbaev S.S. Lobanov 《Russian Geology and Geophysics》2013,54(10):1288-1304
We present petrological, isotopic, and geochronological data on gabbro-picrite plutons from the Altai collisional system of Hercynides (eastern Kazakhstan). The geological, geochemical, and geochronological data suggest that these rocks are indicators of the activity of the Tarim plume. The gabbro and picrites formed in two stages (~293 and 280 Ma) in an acid-to-basic succession, explained by a model for the interaction of thermochemical plumes with the lithosphere. Early igneous activity, which gave rise to subalkalic gabbro plutons, reflects the first interaction between the ascending plume and the lithosphere, with low-melting sublithospheric protoliths. Further interaction was characterized by the sublithospheric spread of the plume head with intense heating of the lithospheric base and possible intrusion of deep melts, which resulted in the formation of Cu–Ni–PGE gabbro-picrite plutons in the Altai collisional system and Northwest China. 相似文献
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S. V. Khromykh A. A. Tsygankov G. N. Burmakina P. D. Kotler E. N. Sokolova 《Petrology》2018,26(4):368-388
The paper reports results of petrological-geochemical, isotope, and geochronological studies of the Preobrazhenka gabbro–granitoid massif located in the Altai collisional system of Hercynides, Eastern Kazakhstan. The massif shows evidence for the interaction of compositionally contrasting magmas during its emplacement. Mineralogical–petrological and geochemical studies indicate that the gabbroid rocks of the massif were formed through differentiation of primary trachybasaltic magma and its interaction with crustal anatectic melts. Origin of the granitoid rocks is related to melting of crustal protoliths under the thermal effect of mafic melts. The mantle–crust interaction occurred in several stages and at different depths. A model proposed here to explain the intrusion formation suggests subsequent emplacement of basite magmas in lithosphere and their cooling, melting of crustal protolith, emplacement at the upper crustal levels and cooling of the granitoid and basite magmas. It was concluded that the formation of gabbro-granitoid intrusive massifs serves as an indicator of active mantle–crust interaction at the late evolutionary stages of accretionary–collisional belts, when strike-slip pull-apart deformations causes the high permeability of lithosphere. 相似文献
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A. V. Travin D. S. Yudin A. G. Vladimirov S. V. Khromykh N. I. Volkova A. S. Mekhonoshin T. B. Kolotilina 《Geochemistry International》2009,47(11):1107-1124
Structural-petrologic and isotopic-geochronologic data on magmatic, metamorphic, and metasomatic rocks from the Chernorud
zone were used to reproduce the multistage history of their exhumation to upper crustal levels. The process is subdivided
into four discrete stages, which corresponded to metamorphism to the granulite facies (500–490 Ma), metamorphism to the amphibolite
facies (470–460 Ma), metamorphism to at least the epidote-amphibolite facies (440–430 Ma), and postmetamorphic events (410–400
Ma). The earliest two stages likely corresponded to the tectonic stacking of the backarc basin in response to the collision
of the Siberian continent with the Eravninskaya island arc or the Barguzin microcontinent, a process that ended with the extensive
generation of synmetamorphic granites. During the third and fourth stages, the granulites of the Chernorud nappe were successively
exposed during intense tectonic motions along large deformation zones (Primorskii fault, collision lineament, and Orso Complex).
The comparison of the histories of active thermal events for Early Caledonian folded structures in the Central Asian Foldbelt
indicates that active thermal events of equal duration are reconstructed for the following five widely spiced accretion-collision
structures: the Chernorud granulite zone in the Ol’khon territory, the Slyudyanka crystalline complex in the southwestern
Baikal area, the western Sangilen territory in southeastern Tuva, Derbinskii terrane in the Eastern Sayan, and the Bayankhongor
ophiolite zone in central Mongolia. The dates obtained by various isotopic techniques are generally consistent with the four
discrete stages identified in the Chernorud nappe, whereas the dates corresponding to the island-arc evolutionary stage were
obtained only for the western Sangilen and Bayankhongor ophiolite zone. 相似文献
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E. I. Mikheev A. G. Vladimirov V. S. Fedorovsky T. B. Bayanova A. M. Mazukabzov A. V. Travin N. I. Volkova S. V. Khromykh V. V. Khlestov P. A. Tishin 《Doklady Earth Sciences》2017,472(2):152-158
The western Baikal region (Ol’khon region, Nutgei zone, Kharikta area) is characterized by the development of packets of thrust-type folds and synkinematic granites corresponding to the stage of thrust deformations (overthrust-type granites). Two stages in the formation of thrust-type folds separated by episodes of granite emplacement are definable. The data obtained make it possible to estimate both the time of transition from thrust to strike-slip deformations and the duration of accretionary?collisional events that resulted in regional strike-slip deformations, which terminated in the western Baikal region 460?455 Ma ago. 相似文献
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A.S. Mekhonoshin A.G. Vladimirov V.G. Vladimirov N.I. Volkova T.B. Kolotilina E.I. Mikheev A.V. Travin D.S. Yudin V.V. Khlestov S.V. Khromykh 《Russian Geology and Geophysics》2013,54(10):1219-1235
Early Caledonides in the Olkhon region of western Cisbaikalia, being part of the folded framing of the Siberian craton, are a unique geologic object for studying processes of mantle–crust interaction at deep levels of the Earth’s crust. This paper describes restitic ultramafic bodies and boudins spatially confined to faults (blastomylonite sutures), as well as synkinematic granites related to amphibolite facies of metamorphism. Estimates are given for the PT-conditions of metamorphic rocks from the folded framing of the ultramafic bodies, the chemical and mineral compositions of ultramafic rocks, blastomylonites and synkinematic granites, and the results of U–Pb and Ar–Ar isotopic dating. Particular attention is paid to the thermal history of tectonic exposure of the ultramafic bodies as relics of the paleo-oceanic crust in the Early Caledonian collisional system of western Cisbaikalia. 相似文献
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