THE MAIN ALTERATION TYPE OF AXI GOLD DEPOSIT AND ITS RELATIONSHIP TO GOLD MINERALIZATION

Axi gold deposit, which is occurred in the continental volcanic rocks of Lower Carboniferous Dahalajunshan formation, belongs to typical large gold deposit of adular-sericite type. The mineralization is related to the ring fracture system in the caldera rim(volcanic apparatus). The near-ore wall-rock alteration of the deposit contains mainly silicification, sericitization, adularization, pyrophylitization, chloritization etc. From the main orebody to both sides, the alteration can be zoned into six mineral assemblage zones, i.e., 1)strong silicification zone(auriferous quartz), 2)symmetrical phyllic alteration zone, 3)sericitization zone, 4)propylitization zone, 5)weak sericitization zone and 6)weak propylitization zone, of which the strong silicification and phyllic alteration zones are closely related to gold mineralization.