LA-ICP-MS Zircon U-Pb Age,Geochemical Characteristics And Geological Significance Of Qingbaishan Granite In Beishan Area,Xinjiang

The largest and most complex giant sutures in central Xinjiang of the Central Asian orogenic belt between the Siberian and Tarim plates have developed a significant hyperplastic orogeny in the Xianzhou.As the most typical study area of the Central Asian orogenic belt,the North Mountain area formed by subduction splicing from the late Paleozoic to the early Mesozoic Paleo-Asian ocean to the Tarim plate has attracted much attention.A large area of Paleozoic-Metozoic magmatic rocks are widely exposed in the Northern rift system,which is a study of the Mesozoic orogenic belt in Central Asia The tectonic pattern,geological history and geodynamic evolution provide a good place.The area of Beishan in Xinjiang is located in the northeast margin of Tarim plate,and the study area is located in the area of Yamansu Town and Cihai Iron Mine in East Tianshan Mountain.In this paper,the granite rock mass exposed in the Qingnanshan area of Beishan,Xinjiang,is selected as the research object: the rock mass is distributed south of the Hongliuhe fault,with a rock-based production area of about 90 square kilometers,with a long axis near east-west zonal distribution on the plane,and consists of a series of rock foundations of different sizes.The dating results of amphibole-bearing granite and zircons in n-north and south U-Pb granite samples in the clean mountain area of Beishan show that magmatic activity occurs in 411.6±8.2 Ma and 301.7±2.5,respectively Ma,belonging to the early Devonian and late Carboniferous.The early Devonian rock containing amphibole granite is a series of calc-alkaline to high potassium calc-alkaline,which is a kind of quasi-aluminum I type granite.The trace elements have the characteristics of Th?U and K?Rb enrichment,Nb P?Ti and other loss,and the source of magma is the mixed source of shell and mantle.Late Carboniferous syenite is a A type granite with high potassium calc-alkaline.mainly derived from the lower crust,probably due to mantle-derived magmatic ascending bottom invasion melting from the loss-making mantle from the young lower crust material,and experienced a certain degree of separation crystallization.The magmatic activity of the early Devonian rock mass and the late Carboniferous rock mass formed in the subduction-plastic orogenic environment and the post-collision environment during the closing process of the ancient Asian ocean in the Beishan area,respectively,representing the geotectonic processes between the early Devonian rock mass and the late Carboniferous in Beishan area,respectively...