江西九瑞地区两个成矿系列的铜矿床

COPPER DEPOSITS OF TWO METALLOGENIC SERIES IN JIURUI AREA, JIANGXI PROVINCE

九瑞地区是长江中下游铜矿床的主要矿田之一。其铜矿可分成两个成矿系列:一是与海底喷气沉积活动有关的矿床;另一是与浅成超浅成侵入活动有关的矿床。上述不同成因的铜矿床常常可以叠加在一起,形成复成因矿床,即所谓“三位一体”铜矿床。本文根据九瑞地区城门山、武山、封三洞等矿区的矿床地质特征、成矿地质环境等对两个成矿系列铜矿床进行了对比。

The iron-copper ore deposits in Middle-Lower Yangtze Reaches, of which Jiurui is one of the important ore areas, might be grouped into two metallogenic series. One consists of ore deposits related to submarine exhalative activities, formed through exchange of hydrothermal fluids with seawater in the submarine environment. In this area, the stratabound deposits between clastic rocks and carbonate rocks on the bottom of Upper Carboniferous Huanglong Formation are assigned to this series, which includes hematite-siderite deposits, copper-bearing pyrite deposits, copper-bearing pyrrhotite deposits and pyrite deposits. The other refers to ore deposits related to intermediate-acid hypabyssal to supra-hypabyssal intrusive activities, which lie along the contact zone between the intrusive body and the Carboniferous-Permian carbonaceous rocks or within the intrusive body itself and include skarn-type iron-copper deposits, porphyry type copper-molybdenum deposits and veinlike copper-gold deposits. These copper deposits of different geneses are often superimposed on each other, forming polygenetic or so-called 'trinity' deposits. Based on geological data of Jiuriu area, this paper makes a comparison between copper deposits of these two metallogenic series in such aspects as geological characteristics, ore-froming geological environment, ore fabrics, trace elements,stable isotopes,thermodynamic condition for mineralization,ore-forming mechanism and ore-prospecting directions.