Abstract:
This paper is the result of mineral exploration engineering.
Objective The genesis of vein quartz is a key factor affecting the quality of high-purity quartz. To reveal the quality differences and controlling factors of vein quartz of different genetic types, this study compares magmatic-hydrothermal vein quartz from the Jiajika area and metamorphic-hydrothermal vein quartz from the Danba area in western Sichuan, providing a basis for high-purity quartz exploration.
Methods Optical microscopy, cathodoluminescence (CL), laser Raman spectroscopy (LRM), in situ LA-ICP-MS microanalysis, and purification experiments were used to investigate the petrographic features, fluid inclusions, and trace-element characteristics of quartz.
Results The Jiajika vein quartz inherited the characteristics of Li-rich granitic magma and is significantly enriched in Al and Li, with average contents of 59.19×10−6 and 12.33×10−6, respectively. Its fluid inclusions are dominated by intragranular secondary inclusions. The Danba vein quartz, affected by metamorphic deformation, is characterized by relatively low Al and Li contents, with average values of 22.42×10−6 and 2.34×10−6, respectively. Its fluid inclusions are mostly transgranular secondary inclusions. Purification experiments show that the SiO2 purity of Danba vein quartz can reach 99.997% (4N7 grade), which is higher than that of Jiajika vein quartz, with purities of 99.991% (4N1 grade) and 99.992% (4N2 grade).
Conclusions Metamorphic deformation is beneficial for reducing the content of lattice-bound impurities in quartz and improving the removability of inclusions. The Danba metamorphic-hydrothermal vein quartz therefore has better resource quality. Gneiss domes and metamorphic core complex areas are prospective targets for the exploration of similar high-quality high-purity quartz raw materials.
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