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The Fe- and Al-rich metapelite of the Teiskaya Group in the trans-Angara part of the Yenisei Range are characterized by variable P-T parameters of their metamorphism. Geochemical data on these rocks were used to reproduce the nature and composition of their protolith. The metapelites were determined to be redeposited and metamorphosed Precambrian weathering crusts of the kaolinite type, which were produced by the erosion of Archean rocks of predominantly acid (granitoid) composition in shallow-water continental-margin basins in a humid climate. These results are consistent with the results of the lithological-facies analysis and geodynamic reconstruction of the Precambrian geological evolution of complexes in the Yenisei range. Differences were revealed between the REE patterns in metapelites in various metamorphic zones caused by both the compositional heterogeneity of the protoliths and the prograde (in terms of pressure) mineral reactions of collision metamorphism with the predominant effects of various processes during different evolutionary stages. 相似文献
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A. D. Nozhkin I. I. Likhanov K. A. Savko V. V. Reverdatto A. A. Krylov 《Doklady Earth Sciences》2018,479(1):347-351
The results of thermobarometry yielded the P–T parameters of formation and evolution of sapphirine- bearing granulites in the Anabar shield with peak values of UHT metamorphism in the range of T = 920–1000°C at P = 9–11 kbar. Isotope–geochronological data indicate a polymetamorphic evolution of these rocks. Detrital zircon cores in the center of crystals yielded ages of 3.36, 2.75, 2.6, and 2.5 Ga. Later, superimposed metamorphic transformations of the detrital zircon formed rims dated to 2.4, 2.3, 2.2, and 1.83 Ga. A potential provenance source of the detrital zircons could be hypersthene plagiogneisses and metabasics of the Daldyn Group with a premetamorphic age no less than 3.32 Ga and products of their metamorphism of about 2.7 Ga old. 相似文献
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The geodynamic nature of the Late Neoproterozoic island-arc dacites (691 ± 8.8 Ma) and rift basalts (572 ± 6.5 Ma) of the Kiselikhinskaya Formation, Kutukasskaya Group, in the Isakovskii terrane is inferred from geochemical data and U–Pb zircon (SHRIMP-II) dates. The volcanic rocks were produced during the late evolutionary history of the Yenisei Range, starting at the origin of oceanic crustal fragments and their accretion to the Siberian craton to the postaccretionary crustal extension and the onset of the Caledonian orogenesis. The reproduced sequence of geological processes marks the early evolution of the Paleo- Asian Ocean in its junction zone with the Siberian craton. The data refine the composition and age of volcanic rocks in the trans-Angara part of the Yenisei Range and specifics of the Neoproterozoic evolution of the Sayan–Yenisei accretionary belt. 相似文献
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Doklady Earth Sciences - 相似文献
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Doklady Earth Sciences - Geochemical and isotope–geochronological evidence of Late Riphean intraplate magmatism within the Chernorechenskii massif at the western margin of the Siberian Craton... 相似文献
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Babichev A. V. Reverdatto V. V. Polyansky O. P. Likhanov I. I. Semenov A. N. 《Doklady Earth Sciences》2019,486(2):706-710
Doklady Earth Sciences - The effect of heat generation due to friction in faults under the conditions of shear and thrust was evaluated by computer modeling, and 3D and 2D thermomechanical... 相似文献
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Geotectonics - The article proposes a model of collisional and accretionary events of the Neoproterozoic at the western margin of the Siberian Craton based on the results of geological,... 相似文献