Литосфера (Feb 2018)
Structural peculiarities and geodynamic evolution of Taimyr Peninsula in the Neoproterozoic
Abstract
Structural relationships between the Neoproterozoic rock complexes of a continental massif, island arc with rear reef and back-arc basin geodynamic affinities are described and considered in this work based on field observations within the northeastern segment of the Central Taimyr tectonic zone distinguished in the late Hercynian fold-thrust belt of Taimyr Peninsula. As established for the first time, rock complexes of the continental massif with the early Late Riphean (Tonian-Cryogenian) volcanogenic-sedimentary cover occur in the study region as allochthonous syn- and post-sedimentary thrust sheets buried in or thrust over deposits of a back-arc basin, which accumulated in the terminal Late Riphean (Cryogenian)-initial Vendian (Ediacaran). Some sedimentary events in the basin observs as a result of thrusting. These and other results of observations elucidate important details of the tectonic development in the Late Precambrian, when two lateral ensembles of the Neoproterozoic structures originated in the region. In the first half of the Neoproterozoic, the regional tectonic ensemble included the oceanic plate abutting on the continental massif with the suprasubduction volcano-plutonic belt and accretionary wedge in front of it. The subsequent system of an island arc upon accretionary wedge and marginal back-arc basin with new oceanic crust originated in the second half of the Neoproterozoic and existed approximately till the mid-Ediacaran phase of the intense formation of arc-ward vergenced thrust sheets and folds. The next Late Baikalian phase of tectogenesis turned the Central Taimyr zone into the accretionary orogen merged into the Siberian craton as the newly formed part of the passive continental margin. Probable cause of the Baikalides origin is observed too.
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