西成矿田洛坝矿床含矿层物性特征及成矿条件分析

The physical characteristic and ore-forming conditions of the Luoba lead-zinc deposit in Qinling,China

采用压汞分析技术对秦岭多金属成矿带西成矿田洛坝铅锌矿床含矿层各岩系的物性特征进行了研究,结果表明含矿层各岩系物性特征具有孔隙度小、渗透率低、孔喉连通性差的特点,这一特征对洛坝大型矿床的形成是极为不利的。结合该矿床成矿期盆地水体较浅的特征,可以说明后期的构造运动对洛坝矿床的形成起了决定性作用。一方面,后期构造运动除了形成褶皱和断裂外,还形成大量的微裂隙、缝隙、虚脱部位,为洛坝矿床的形成提供了储集空间;另一方面,后期构造运动形成的断裂、微裂隙、缝隙提高了孔隙间的连通性,使水岩反应得以进行,成矿元素从碳酸盐岩地层中淋滤出来随成矿流体运移参与成矿。

Based on the pressure curve experiment, the physical characteristic of ore-bearing rocks of the Luoba lead-zinc deposit in the Qinling Xicheng deposit field shows small porosity, low permeability and bad link ostiole in the ore-bearing rocks series. The feature indicates that the physical characteristic of ore bearing is unfavorable for forming the Luoba lead-zinc deposit. Combined with the shallow water of the basin at the same geologic time, the tectonic movement acted a key role in forming the Luoba lead zinc deposit. On the one hand, the succeeding tectonic movement formed a lot of micro-fissures, cracks and collapse locations, and these tectonic cracks provided reservoirs. On the other hand, the micro-fissures and cracks increased linking ability between pores, and the linking ability improved reaction between water and rocks, The ore forming elements leached from carbonate moved alone with ore fluid and formed the deposit.