Geochemistry of metavolcanics in the southern Hövsgöl area (northern Mongolia): geodynamic implications
A.Ya. Medvedeva, I.V. Gordienkob, M.A. Gornovaa, A.I. Almukhamedova
aVinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, 1a ul. Favorskogo, 664033, Irkutsk, Russia
b Geological Institute, Siberian Branch of the Russian Academy of Sciences, 6 a ul. Sakhyanovoi, Ulan Ude, 670047, Russia
Keywords: Metavolcanics; protolith; accretionary prism
Pages: 245-253
Subsection: PETROLOGY, GEOCHEMISTRY AND MINERALOGY
Abstract
The lava sequence of the Alag-Zaar-Gol River catchment (southern Hövsgöl area, northern Mongolia) is an accretionary prism composed of metamorphosed basalt and, less often, andesite alternating with siliceous tuff. The protolith of metabasalts may have formed in island-arc or ocean-island environments, and andesites were, possibly, derived from ocean-island varieties. Volcanics of different types are found coexisting within the same thrust sheets, which may be due to thrusting in the course of postmagmatic tectonic events.
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