Mesoproterozoic Continental Arc Type Granite in the Central Tianshan Mountains: Zircon SHRIMP U-Pb Dating and Geochemical Analyses

The Central Tianshan belt in northwestern China is a small Precambrian block located in the southern part of the Central Asia Orogenic Belt (CAOB),which is considered as"the most voluminous block of young continental crust in the world"that comprises numerous small continental blocks separated by Paleozoic magmatic arcs.The Precambrian basement of the central Tianshan Mountains is composed of volcanic rocks and associated volcano-sedimentary rocks that were intruded by granitic plutons.Geochemical analyses demonstrate that the granitic plutons and volcanic rocks were generated in the Andean-type active continental arc environment like today's Chile,and the zircon U-Pb SHRIMP dating indicates that they were developed at about 956 Ma,possibly corresponding to the subduction of the inferred Mozambique Ocean under the Baltic-African super-continent.