EARLY PERMIAN ADAKITES OF THE NORA-SUKHOTINO TERRANE IN THE EAST OF THE CENTRAL ASIAN OROGENIC BELT: GEOCHRONOLOGICAL (U-Pb, LA-ICP-MS) AND GEOCHEMICAL DATA
Yu. V. Smirnov1, V.B. Khubanov2
1Institute of Geology and Nature Management, Far Eastern Branch of the Russian Academy of Sciences, Blagoveshchensk, Russia
2Dobretsov Geological Institute, Siberian Branch of the Russian Academy of Sciences, Ulan-Ude, Russia
Keywords: Nora-Sukhotino terrane, early Perman, adakites, geochemistry, U-Pb data
Abstract
We present results of geochemical and geochronological (U-Pb, LA-ICP-MS) studies of plagiogranites of the Mt. Zmeinaya massif in the Nora-Sukhotino terrane. The studied rocks are of calc-alkaline series and peraluminous type. They formed in collision settings at the final stage of evolution of the Nora-Sukhotino terrane. The high Sr/Y ratios and low Y and Yb contents of the plagiogranites indicate that these are adakitic rocks. The trace element composition of the rocks suggests their high-pressure (>15 kbar) genesis through the melting of metabasites. The youngest zircon population from the plagiogranite has a mean weighted concordant age of 295 ± 4 Ma, which corresponds to the early Permian. With regard to the zircon morphology, the obtained age can be considered the age of the plagiogranites.
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