Литосфера (Aug 2018)
Plumes - a new word in Geology of the Urals
Abstract
Subject. The ideas of plume tectonics became active and developing only several years later than the theory of plate tectonics. But in the Urals, the question of plume tectonics, contrary to plate tectonics, was not raised, with rare exceptions, until the latest decade. It is explained by great difficulties in revelation of plumes in any ancient foldbelt, because seismic tomography is not applicable, and magmatic complexes are partly covered by younger sediments, partly eroded, and, additionally, undergone distortion, connected with continental break-ups and drift, subduction and fold-and thrust deformations. Materials and methods. However in recent years, among the magmatic complexes of the Urals (mostly in its western areas), Pay-Khoy and Novaya Zemlya, thanks to precise definition of magmatic formations ages, study of their geodynamically conditioned petrochemistry and their correlation with other regions, the author identified ten levels of probable manifestations of plume/superplume events. Results. It is assumed that in the modern Urals the relics of the following plumes: Navysh (Lower Riphean), Mashak (Middle Riphean), Arsha and Kiryabinka (Terminal Riphean), Mankhambo (Cambrian), Kidryas (Lower-Middle Ordovician, Ushat (Late Ordovician-Lower Silurian), Kola-Dniepr (Devonian), Stepninsk (Permian), Ural-Siberian (Lower-Middle Triassic) had remained.
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