The Petrogenesis And Forming Setting Of The Daniujuan-Wuqihaxi Pluton In The Toudaoqiao Area,Inner Mongolia

The tectonic evolution process of the Xingan and Songnei blocks, and their closure time along the Hegenshan-Nenjiang-Heihe amalgamation belt are still controversial.The Daniujuan-Wuqihaxi pluton, formed in the late Paleozoic, is located at 8KM of the southeastern Toudaoqiao area, its tectonic setting, origin and characteristics well constraint to the process of the integration and closurd time of the Hegenshan-Nenjiang-Heihe amalgamation belt. Due to lack of systematic investigations of the invasive petrology, chronology, petrochemistry and lithogeochemistry of the granite rocks in the southwest extension region of the invaded zone formed in the late Paleozoic, causes and forms of the intrusive rock belt of southwest tectonic backgroundare still not clear. This paper conducted a systematic study on petrology, chronology, petrochemistry and lithogeochemistry of the Daniujuan-Wuqihaxi pluton formed in the late Paleozoic in the Toudaoqiao area in order to provide the basis for the closure time of the Hegenshan-Nenjiang-Heihe amalgamation belt.The Daniujuan-Wuqihaxi pluton in the Toudaoqiao area, Inner Mongolia is mainly consists of monzonitic granite and granite, its evolution sequence of petrology is quartz monzodiorite ? granodiorite ? monzonitic granite ? granite. The Daniujuan-Wuqihaxi pluton shows the characteristics of calcium alkaline rock series, has strong peraluminous series series. These rocks are enriched in elements of Rb?Th?U?K?La?Nd?Zr?Hf while depleted in elements of Nb?Sr?P?Ti. Their characteristics of petrochemistry and geochemistry indicate that they are S-type granite formed by partial melt lower crust. They have the same special mineral assemblage(The granitic rocks in the research area contain special minerals such as mica, garnet, etc.)and petrochemical characteristics and lithogeochemical characteristics of post-collision granite. They are formed by the Xingan and Songnen blocks along the Hegenshan-Nenjiang-Heihe amalgamation belt in post-orogenic stage.