1. Geological Institute,Russian Academy of Sciences,Moscow 119017,Russia
2. A.N.Zavaritsky Institute of Geology and Geochemistry,Ural Branch of the Russian Academy of Sciences,Yekaterinburg 620016,Russia
折叠
Abstract
The combined petrographic,petrological,geochemical and geochronological study of the Neoproterozoic gneisses of the Sarychabyn and Baskan complexes of the Junggar Alataw of South Kazakhstan elucidate the Precambrian tectonic evolution of the Aktau-Yili terrane.It is one of the largest Precambrian crustal blocks in the western Central Asian orogenic belt.The U-Pb single-grain zircon ages indicate that granite-gneisses formed from the same source and crystallised in the early Neoproterozoic ca.930-920 Ma.The chemical composition of gneisses corresponds to A2-type granites.The whole-rock Nd isotopic characteristics(εNd(t)=-4.9 to-1.0 and TNd(DM-2st)= 1.9 to 1.7 Ga)indicate the involvement of Paleoproterozoic crustal rocks in magma generation.Early Neoproterozoic ca.930-920 Ma A-type granitoids in the Aktau-Yili terrane of South and Central Kazakhstan might reflect within-plate magmatism adjacent to the collisional belt or a local extension setting in back-arc areas of the continental arc.
Key words
granitoid magmatism/geochemistry/geochronology/Sm-Nd isotope systematics/Neoproterozoic/Junggar Alataw/Kazakhstan/Central Asian orogenic belt
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基金项目
Russian Science Foundation(RSF)(22-77-00082)
plans of the scientific research of the Geological Institute of the Russian Academy of Sciences()
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NSTL
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