金顶铅锌矿床含矿层沉积环境及成矿条件分析

金顶铅锌矿床下含矿层(原地沉积层)的沉积环境分析表明,该层形成于蒸发盐湖相环境,具有水深较浅、沉积速率较快的特点,这样的沉积环境不利于超大型矿床的形成.异地岩系是金顶超大型铅锌矿床形成的决定性条件:花开左组地层具有渗透率低、排驱压力大的特点,是较好的盖层条件;景星组地层具有孔隙度高、渗透率好、孔隙间连通性极好的特点,是有利的储集层.原地沉积岩系除了为矿床的形成提供部分容矿空间外,也是阻止成矿流体下渗的必不可少的遮挡层.

Analysis of the ore-bearing strata sedimentary environment and mineralization geological conditions of the Jinding lead-zinc deposit, Yunnan, China

The sedimentary environment of the ore-bearing strata is investigated in this paper based on the evidences of lithology,color,granularity analysis,facies indictor,geochemical data,and so on.The research shows that the lower orebearing strata probably are deposited in evaporate salty lake.It is believed that the super deposits are not able to form in this geological condition because of its shallow depth and rapid sedimentary rate.But the overthrusting strata make it become possible.First,the Huakaizuo Formation(J_2h) strata are better covers due to the low permeability and high displacement pressure,and second,the Jingxing Formation(K_1j) strata are better reservoirs due to the high porosity and permeability and a better interconnecting.The intrabasinal strata system is composed of Yunlong Formation(Ey). The upper member of Yunlong Formation(Ey~(a)) is a good barrier due to its low permeability and a bad interconnecting,but the lower member of Yunlong Formation(Ey~(b)) is a better ore-bearing layer.