海南岛西部戈枕含金剪切带及其金矿成矿系列

THE GEZHEN AURIFEROUS SHEAR ZONE AND RELATED METALLOGENIC SERIES IN WESTERN HAINAN ISLAND

古生代以来，海南西部戈枕含金剪切带至少经历了三次类型不同的构造变形，并发生了三次相关的金矿化。该剪切带的构造变形，在加里东旋回发生于抱板群矿源层下构造层次，表现为韧性剪切，其晚期形成含金长英质脉；在海西－印支旋回发生于中构造层次，表现为韧－脆性变形，形成糜棱岩型和石英脉型金矿床；燕山旋回的构造变形发生于上构造层次，表现为脆性特征，并伴有岩浆热液作用，形成最具工业价值的破碎蚀变岩型金矿床。本文在此基础上提出了含金剪切带型金矿成矿系列概念，具体厘定出红甫门岭糜棱岩型、不磨石英脉型及北牛破碎蚀变岩型三种矿床式，并总结了含金剪切带构造成矿四阶段模式。

The Gezhen auriferous shear zone controlling all gold deposits in western Hainan island underwent at least three times of structural deformations and three related mineralizations. At an earlier stage it was formed in Caledonian cycle,allocated in the contacting zone between western Hainan terrain and eastern Hainan terrain, and featured by ductile rheologic deformation, while in the later stage auriferous felsic veins were formed.In Hercynian Indosinian cycle the Gezhen auriferous shear zone underwent superimposition of ductile brittle deformation. The zonation of deformation intensity of such structure has a close connection with spatial location and zonation of gold ore types. Mylonite type gold deposits occur in the center of northeast part of the shear zone characterized by ductile deformation, strong strain and stress concentration, whereas gold quartz veins lie on the margin or in the southwestern part of the shear zone characterized by weak deformation intensity, dispersal stress and ductile brittle deformation type. In Yanshanian cycle the Gezhen shear zone was transformed by brittle deformation with magmatic hydrothermal activity, forming shatter altered rock type gold deposits. Mylonite type, quartz vein type and shatter altered rock type gold deposits constitute a whole metallogenic series for the auriferous shear zone, with the three types of deposits named Hongfumenling type, Bumo type and Bainiu type. In addition, based on researches of geological features of the three types of deposits, the authors set forth the ore controlling role of source bed, metallogenic fluids and physicochemical parameters, and put foward four stage metallogenic model for auriferous shear zone according to the isotopic age data for relationship between the shear zone and the gold mineralization.