对鄂北早寒武世重晶石矿与生态关系的探讨

本文讨论的重晶石矿床,分布在随州市南部和京山县北部。含矿岩系为早寒武世余家冲组下部的黑色硅质岩系。由硅质岩、硅质板岩、粉砂质板岩、板岩及白云岩组成。与重晶石矿层伴生的磷块岩、黄铁矿及钒、钼、铀等多金属元素,在局部地段可富集成小矿体。矿层中发现丰富的遗迹化石:Chondrites bollensis(粒线丛藻迹),重晶石沿造迹生物扰动层富集,形成不同类型矿石。扰动强烈时,原始层理被破坏,形成薄层块状纯净矿石。扰动轻微时,原始沉积物保存较多。重晶石沿遗迹穴管富集,形成偏豆状含杂质较多的矿石。造迹生物代谢活动形成的小生态环境与局部成矿活动是密切相关的。笔者在重晶石矿层中发现的大量遗迹化石,不仅为生物控制成矿理论提供了直接的证据,而且为重新评价该矿床提供了依据。

ON RELATIONS BETWEEN ECOLOGY AND BARITE ORES IN THE EARLY CAMBRIAN OF NORTHERN HUBEI

The barite ores mainly occur in southern Suizhou City and northern Jingshan County. The barite ore-bearing series consist of siliceous rock, siliceous slate, silty slate, slate and dolomite. In the lower Yujiachong Formation of the Early Cambrian, the ores are accompanied by phosphorite, pyrite and polymetal elements like vanadium, uranium and molybdenum, which can be enriched to form small ore deposits locally. There are many trace fossils in the ore beds which can be divided into two types: one is the pure thin-bedded ore formed when bioturbation is intensive and the original bedding is destroyed; the other is the impure lenticular cave-and tube-filling ore formed when bioturbation is relatively weak and the original bedding is well-preserved. So the metabolism of trace-making organism is closely related to local ore-forming process.