安徽铜陵马山层控金铜硫矿床成因

安徽铜陵马山金铜硫矿床产于中石炭统黄龙组白云岩与灰岩地层之间,主矿体呈层状。矿石结构构造、成矿元素地层学分带、硫化物矿物微量元素地球化学和硫、铅同位素等特征表明,该矿床是中石炭世海底喷流沉积的块状硫化物矿床,成矿后在燕山期又受到了石英闪长岩体的改造和叠加。在长江中、下游断裂拗陷带中有许多硫化物矿床在成因上与马山相似。研究表明,在晚古生代,有一片洋壳拖着扬子板块往北向华北板块俯冲,故这类矿床形成于扬子古陆北缘的被动大陆边缘环境。

GENESIS OF THE MASHAN Au-Cu-S DEPOSIT, TONGLING, ANHUI PROVINCE

The main ore body of Mashan gold-copper sulphur deposit in Tongling, Anhui Province is in stratiform occurring between the dolomite and limestone of the Middle Carboniferous Huanglong Formation. Ore textures and structures, stratigraphicalzoning of ore forming elements, trace element geochemistry of sulphide minerals, and sulphur and lead isotopes indicate that it is a Carboniferous Sedex massive sulphide deposit that was exposed to reworking and overprinting of Yanshanian quartz diorite intrusion. A number of sulphide deposits are similar genetically to the deposit in the lower Yangtze fault depression zone. In late Palaeozoic, an oceanic crust, with the Yangtze plate being anchored on its southern side, was subducting northwards beneath the North China plate. It follows that these deposits were originally formed on the passive continental margin north to the Yangtze plate.