The Genetic Mineralogical Study Of Garnet-bearing Granite In Jinshuikou, The East Kunlun Orogen

Garnet-cordierite granite of jinshui is an important part of East Kunlun orogenic belt, so the genetic study to explore the East Kunlun orogenic formed in the early Paleozoic evolution is of great significance. Garnet, as a important accessory minerals in the granite is more sensitive to forming of environment. Through the study of the mineralogical studies of garnet-cordierite granite and obtained as follows:(1) According to the different forms of garnet, structure and composition characteristics. The garnet has two different genetic types:magma type garnet and residual type garnet. Magma type garnet:garnet occurrence in single grain output, and good diomorphism. The garnet nearly contains inclusions and display the typical "clock" Mn band, be supposed to the mineral of the late magmatic crystallization, and visible under a microscope. Residual type garnet:garnet size for 0.5-1 mm, most has crack, and irregular granular edge. Edge corrosion often become mica, has quartz inclusions and visible to the naked eyes. Components of garnets have enrichment of MgO (2.9%～5.9%) and poor MnO (0.16%～3.3%), the characteristics of pyrope components is on average 19.59%, up to 35.38%. Cordierite high Mg ingredients that are alsodue to join of the granulite melt composition.(2) Biotite is given priority to with magnesia biotite, contains a small amount of iron black mica, black mica rich Mg speculated that is associated with the join of granulite inclusions melting.(3) Zircon cores age value roughly between 1200 Ma and 1600 Ma, obviously has the characteristics of Precambrian detrital zircon age; Configuration has the characteristics of magmatic zircon, but Th/U ratios features (< 0.1) was caused by the anatexis characteristics of magmatic origin.(4) Combination with rock geochemistry and isotopic data, we think the Jinshuikou garnet-cordieritegranite is the anatexis results of Baishahe Formation supracrustal rocks and basic granulite with melting temperature above 678℃。...