安徽向山地区火山岩层中硬石膏的沉积成因特征及其与硫铁矿的关系

SEDIMENTARY GENESIS OF ANHYDRITE DEPOSITS IN THE BOLCANICSERIES AND THEIR RELATION TO THE PYRITE DEPOSITSIN XIANGSHAN DISTRICT ANHUI PROVINCE

本文从赋矿地层,含矿层序、容矿岩性、矿石结构构造、矿物组合、生成顺序、地球化学特征以及区域对比等方面,论证了向山地区的硬石膏矿床是在蒸发环境条件下,主要由火山喷气作用提供物质来源,通过沉积作用所形成的特殊膏盐建造,并受到后期岩浆热液的叠加改造。文章还分析了硬石膏形成的地质环境条件。最后阐述了该区硫铁矿与硬石膏的两种成因关系。

Based on its ore-occuring horizons, ore bearing sequeces and also its host rocks, sedimentary structures and textures of ores, some geochemical characteristics and areal correlation, the Xiangshan anhyrite deposits, in the middle part of the Nanjing Wuhu volcanic basin, are not either of hydrothermal genesis, or of typical evaporite deposits. They were substantially deposited in a faulted volcanic depression under evaporite conditions and with a particular material source volcanic exhalations. They were also transformed and sup erimposed by late magmatic hydrothermalism, being of both sedimentary and hydro thermal geneses. Their formative conditions are determined as well. In addition, two genetic relationships between anhydrite and pyrite deposits in this area are analized, i.e.: (1) syngenetic relationship and (2) gypsiferous beds as a sulfur source to the formation of the pyrite deposits.