FORMATION MECHANISM OF GOLD-QUARTZ VEINS IN SHEAR ZONE TYPE GOLD DEPOSITS

摘要

The mechanism of formation of gold-quartz veins was studied with reference to the Xi-aoqinling Archean gold mine. Results showed that the ore-hosted faults of many gold deposits occurring in Archean Blocks, which is almost syn-tectonic shear zone type deposits, were formed by hydraulic fracturing through driving of tectonic stress, that is, ore-bearing fluid promoted cracks to generate and propagate, and then the fractures were formed i thereafter the fluid was quickly pumped into and precipitated in them, and then the fractures were sealed. Unceasing supply and precipitation of the fluid produced cyclic fluctuations in fluid pressure, which controlled the periodic "crack-seal" of the fracture-vein systems and thus multiperiodic composite gold-quartz veins were formed.