1. The surrounding rock of the pegmatite veins is the older gneiss; 2. The pegmatite veins of Tuguiwula and Wulashan in Inner Mongolia are widely distributed, but there is no granite that has a genetic relationship with them; 3. The metamorphic rocks around the muscovite mining areas in Sichuan, Henan, Shaanxi, Qinghai and other places are subject to strong mixed lithology and granitization, and the phenomenon of transition from mixed rock to pegmatite can be observed; 4. The isotopic age of mica-containing pegmatite in the Altai region of Xinjiang is 219 Ma, and the age of metamorphic rocks is 228 Ma, which are very close. It can be concluded that the muscovite deposit is produced through multiple stages of metamorphism, granitization and pegmatization. The felsic mixed rock→mixed granite→ pegmatite vein is a continuous gradual process. During this process, the content of SiO2, CaO and Na2O decreases, while Al2O3, K2O and H2O are gradually enriched. In this process of change, there is a sudden change in the chemical composition, called the pegmatite lithology. Active Carbon Non Woven Fabric Non Woven Cotton,Non Woven Carbon Fiber,Non Woven Filter Fabric,Active Carbon Non Woven Fabric Ningbo Dokee New Material Co., Ltd. , https://www.aumaterial.com
August 05, 2021