摘要
不整合包括角度不整合和平行不整合两种。不整合面附近成矿是一种比较常见的现象 ,但通常只简单地认为不整合面只是成矿的有利通道和储矿场所 ,而对发生在不整合面中的后期构造活动主动促进成矿 (成矿流体流动 )的作用认识不足。文中在列举了国内外一批产于不整合面中的矿床的基础上 ,总结了这类矿床的主要特点是 :矿床均产于不整合面及其靠近的盖层和基底地层中 ,常呈矿产密集区分布 ,规模一般较大 ,品位较富 ,矿床的成矿过程一般是经过沉积和热液叠加两个阶段 ,成矿作用和围岩蚀变都是以低温为主 ,矿床的成矿元素与同区域的其他类型矿床相似 ;两种不整合面中的矿床的矿体形态与产出位置不大一样。
Unconformity contains two types: disconformity and clino-unconformity. Mineralization occurred near the unconformable contact is an ubiquitous phenomenon. The unconformable contact was usually considered as a good transporting channel and a depositing room for ore-forming fluid. However, it has not yet been seriously considered that the structural movement of later stages occured in the unconformable contact might play a big role in the mineralization(or the transportation of ore-forming fluids). On the basis of lots of ore deposits that occurred on unconformable contact, we have summed up the main characteristics of them as follows: all ore deposits occurred on unconformable contact or near basement and cover strata, usually distributed as mineral concentration regions with large reserves and high grade; the mineralization process of these mineral deposits is of two stages: the sedimentary stage and the hydrothermal superposing stage, in which the alteration of wall rocks occurred mainly under low temperature; the ore-forming elements of this kind of deposit are nearly the same as those of other types of deposits in the same area; but in two different types of unconformable contact the shape of ore body and the place of mineral deposits are different. Finally, we discuss why there are no unconformable type of uranium deposit in China, and why the deposits occurred in the unconformable contact in China are mainly characterized by epithermal types.
出处
《地学前缘》
EI
CAS
CSCD
2004年第2期353-360,共8页
Earth Science Frontiers
基金
国家重大基础研究规划项目 ( 973项目 ) ( 2 0 0 1CB40 980 8)
关键词
不整合面
矿床特征
成矿机制
unconformable contact
characteristics of mineral deposits
mineralization mechanism
