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Natalia V. Lubnina Sergei A. Pisarevsky Victor N. Puchkov Vjacheslav I. Kozlov Nina D. Sergeeva 《International Journal of Earth Sciences》2014,103(5):1317-1334
We present the results of paleomagnetic study of Ediacaran sedimentary successions from the Southern Urals. The analysis of the sedimentary rocks of the Krivaya Luka, Kurgashlya and Bakeevo Formations reveal stable mid-temperature and high-temperature remanence components. Mid-temperature components were acquired during Devonian (Bakeevo Formation) and Late Carboniferous–Early Permian remagnetization events. The high-temperature components in Kurgashlya and Bakeevo Formations are interpreted to be primary, because they are supported by a positive conglomerate test (Bakeevo Formation) and magnetostratigraphic pattern (Kurgashlya Formation). The high-temperature component in the Krivaya Luka Formation is interpreted to be a Late Ediacaran overprint. Our new paleomagnetic poles together with some previously published Ediacaran poles from Baltica and Laurentia are used herein to produce a series of paleogeographic reconstructions of the opening of the Iapetus Ocean. 相似文献
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The features of the kinetics and hydrochemical effects of the exchange-absorption processes in the stratisphere of the Volga-Ural basin are considered. The dependence of these processes on the vertical geochemical zonality and their varied character over the basin depth are shown. The exchange-absorption nature on fresh sodium-hydrocarbonate and saline sodium-sulfate waters in the Upper-Permian sediments of the zone of hypergenesis is proved by the experiments and by physicochemical modeling in the water-terrigenous rock system. The exchange-absorption processes lose their hydrogeochemical significance and play no significant role in the formation of strong brines of the chlorine-calcium type in the zones of cata- and metagenesis under the submersion of Paleozoic and Late Proterozoic rocks to depths over 1000–3000 m. 相似文献
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The geological structure of monzodiorite—granite massifs (Stepninskii, Biryukovskii, Vandyshevskii, and Uiskii) of the Stepninskii complex extending as a chain of intrusive bodies crossing the submeridional structures of the Ural Fold Belt is described. These granite massifs are ascribed to the Permian and, as suggested, are related to a mantle plume. Based on the results of studying melt and gas—liquid inclusions in quartz from granitoids, it was established that the rock crystallization depth in the given series of massifs decreases gradually in the northwesterly direction from hypabyssal to hypabyssal—subsurface facies. It is shown that leucocratic and aplitic varieties of granites with a higher level of fluid content have rare-metal metallogenic specificity and are promising in the search for W—Mo ore mineralization. 相似文献
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The geodynamic origin of volcanic and sedimentary rocks of the Upper Precambrian Arsha Group of the western slope of the southern Urals is considered. It is shown that both rock types are riftogenic/plume in origin. The problem of the spatial and temporal correlation of the Arsha and Karatau groups requires further study. 相似文献
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In order to resolve the age of Navysh volcanics (NV), which is usually attributed to the Lower Riphean of the Ai Formation, we have used geochronological, petrologic, and mineralogical methods of zirconology, apart from the SHRIMP isotopic data of single zircon grains. Moreover, TIMS isotope age analyses have been conducted, the results of which can be regarded as both controlling and providing the most correct information. The TIMS and SHRIMP data make it possible to suggest a polychronous character of the NV, which include not only Riphean, but also Paleozoic groups of volcanics. In this situation, an assessment of the scales of such polychroneity of NV and, correspondingly, of the Ai Formation as a whole becomes urgent. 相似文献
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