宁乡式铁矿床成因的新认识

New views on the genesis of Ningxiang-type iron deposit

鄂西宁乡式铁矿分布广、规模大 ,普遍发育赤铁矿鲕粒。赋矿层位为加里东运动后第一个海浸沉积序列的碎屑岩向碳酸岩的过渡相 ,岩相古地理环境控制作用明显。铁矿层中赤铁矿鲕粒繁多 ,结构复杂 ,与碳酸盐鲕粒成因非常相似 ,为强烈搅动环境中的机械沉积物。经波浪和潮汐水流再次搬运富集 ,最后定位于中、弱环境或相对低凹的近滨相和远滨相上部。

The Ningxiang-type iron deposit in western Hubei is widely-spreading and of large-size and is characterized by hematite ooid.It occurs in the transitional horizon from Caledonian movement and is controlled by lithofacies and palaeography.ln the area hematite ooid is of many types and complex texture that can be comparable to carbonate ooid and formed in intense agitation environment similar to carbonate. After being retransported and enriched by wave and tide process,these ooides form the Ningxiang-type iron deposit which is believed to belong to nearshore facies and upper offshore facies.