Geological Characteristics Of The Permian Intrusive Rocks Along The Bayan Noel Of Alxa,inner Mongolia

The magmatic activity along the northern edge of “Alxa block” is very strong in Early Permian.The genetic research on the evolution process of the collision analysis of between North China plate and Tarim plate has vital significance. The area is located in western Inner Mongolia, andthe north China plate in the tectonic location. The object of study is theearly Permian intrusive rocks in Banner Bayan Noel public area of Alxa Left flag on the basis of field observations, author studied its geological features, geochemical characteristics and geological ages to investigate the age and tectonic environment by collecting and studying previous data.Permian intrusive rocks types in the study area are mainly granodiorite, monzonite granite and syenite granite.From the chemical characteristics of the rocks and various of graphic, the granodiorite, monzonite granite and syenite granite belong to high-K calc-alkaline series.in Bayan Noel study area,Meanwhile enriched light rare earth and large ions Rb, Th, K and other pro-stone elements, Loss of Nb, Ta, Sr, Ti high field strength elements, These geochemical characteristics indicate Early Permian in the northern margin of the North China Plate subduction under ancient Asian Ocean.The granodiorite samples for LA-ICP-MS zircon U-Pb dating method get the weighted average age of 278.1 ± 1.2 Ma; The weighted average age of adamellite was 277.84 ± 0.99 Ma; The weighted average age of syenogranite was 289.53 ± 0.74 Ma. The dating results show that the rocks in the study area mainly formed during the Early Permian.From the geochemical characteristics of rocks in the study area, Rock A / CNK average value is less than 1.1, Rocks in common biotite, magnetite, amphibole,Q, or, ab, an, combination c, hy the emergence of mineral combinations. These characteristics reflect the characteristic of I type granites in the study area.From geological data shows that the northern part of the Alxa region mantle magma strongly involved in the Permian magmatism, this time in the region may be formed in magmatic arc subduction under. Tectonic environment diagram also shows the study area granite subduction process related to the whole, mantle and crust is mixed source.