Genesis of Magma Mixing and Its Geological Implications for Buerkesitai Granite in Tuoli County, West Junggar

Abundant diorite microgranular enclaves exist in Buerkesitai granite and many of them are outside the Adayi gold mine. The enclaves which are highly different in size with typical magmatic structure, such as fine and micro-fine grained texture and porphyritic texture, are in banding distribution. The enclaves show clear boundary or transitional relationships with host rocks. Diorite microgranular enclaves are in good streamline shape like strips or ellipsoid on the whole, showing the characteristics of plastic deformation. The enclaves are parallel to Darbut Fault in longitudinal axis direction. Under the microscope, irregular margins of main minerals, abnormal zoning of plagioclase and unique hollow acicular apatite are developed in enclaves and bands of non-uniform mixing. Abundant melanocratic microgranular minerals can be found in plagioclase xenoliths. These petrographical phenomenon of diorite microgranular enclaves confirm that the genesis of Buerkesitai granite is magma mixing granite. It indicates that intense crust and mantle magma mixing may have had occurred in Darbut tectonic magmatic belt. The fact that diorite microgranular enclaves and the gold mine are in a kind of symbiosis provides new ideas for further study of the source and origin of gold in Darbut tectonic and magmatic belt.