Trachyandesites of the Mogot volcanic field (Stanovoi volcanoplutonic belt, East Siberia): age, geochemical features, and sources

摘要

The performed Ar-40/Ar-39 geochronological studies yielded the first reliable age of trachyandesites of the Mogot volcanic field (115 +/- 3 Ma), which, together with the age of trachyandesites of the Bomnak volcanic field (117 +/- 1 Ma), gives grounds to recognize a new stage (117-115 Ma) of evolution of the Stanovoi volcanoplutonic belt superposed on the igneous and metamorphic complexes of the Dzhugdzhur-Stanovoi superterrane of the Central Asian Orogenic Belt and Stanovoi structural suture. The trachyandesites of the Mogot volcanic field are similar in geochemical features to adakites. Their parental melts resulted from the transformation of Precambrian continental crust under postcollisional extension after the formation of the Mongolo-Okhotsk orogen or under sliding along the boundary between the North Asian craton and the Amurian microcontinent. (C) 2016, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved.