江南元古界层控金矿的地球化学和矿床成因

GEOCHEMISTRY AND METALLOGENESIS OF THE PROTEROZOIC STRATABOUND GOLD DEPOSITS IN THE JIANGNAN AREA, SOUTH CHINA

分布于江南地区的元古界层控金矿床具有典型变质热液和地下水渗滤热液成因之间的一系列地球化学过渡性质,可分为四种矿化类型和四种主要矿化形式。本文研究了这类金矿床的含矿建造和围岩的地球化学特征,揭示了成矿过程中有关元素的富集——贫化地球化学共轭现象。讨论了成矿物质和流体的来源。在以上基础上,提出了该类金矿床改造成因和构造控矿的上升变质热液——下渗地下水环流成矿模式。

The Proterozoic stratabound gold deposits in the Jiangnan area, South China, have many transitional metallogenic features between that of typical metamorphic fluid and infiltrating hydrothermal solution from groundwater in geochemistry and can be classified into four subtypes and four mineralization styles. The present paper studies distribution characteristics of trace elements in gold-bearing formations and wall rock of the gold deposits, reveals a geochemical conjugation relationship between the concentration and impoverishment of Au and related elements in the mineralization process, and energy for forming the gold deposits by the data of trace elements and isotopic geochemistry. On the basis of the above advances, a metallogenic model is proposed of the gold deposits which involves ascending metamorphic fluid and circulating geothermal water under reconstitution and structure control.