Литосфера (Oct 2016)
Carboniferous-Permian magmatism and associated mineralization (Magnitogorsk and East Uralian megazones Southern Urals)
Abstract
The South-Ural accretion-collision fold belt began to form at the final stage of the island-arc development of the Urals. This process correlates in time with the Famennian and Early Tournasian. During the Carboniferous, the subsequent inversion from the island-arc tectono-geodynamic regime to the accretion-collision and transformed shear-riftogenous ones resulted in a considerable increase in diversified magmatic products. We can observe an intricate spatial and temporal combination of magmatic complexes differing in primary sources and genesis of mantle, mantle-crust and essentially crust anatectic magmatic complexes. The existence of the intraplate-type mantle series is associated with the destruction of the subducting oceanic plate and the rise of hot astenospheric diaper plumes up to the basement of the newly-formed lithosphere. The intrusive gabbro-granite magmatism of that time corresponds to the highest chlorine content and the formation of large-scale magnetite skarn mineralization. Along with the intraplate-type magmatic associations and rock series with intermediate features, this geodynamic setting is also characterized by a considerable amount of mantle-crust granitoids of the gabbro-tonalite-granodiorite-granite (GTGG) type formed with multiple manifestations of supra-subduction and crust (lowermost) anatectic processes. For these stages in the formation of the Hercynian South-Ural orogen, we have established a number of tectono-magmatic stages characterizing the magmatism of such tectonic events that accompanied the attachment of the Magnitogorsk Palaeo Arc and the eastward heterogeneous accretion assemblage to the margin of the East European Plate. Another goal of this paper is to typify the Permian granitoid magmatism, where mantle-crust gabbro-montzodiorite-granite latitic (282-274 Ma) and crust-palingenous granitic (290-276 Ma) and leucogranites (275-260 Ma) series were synchronously formed.
