牛角塘伴生型镉矿床特殊的成矿环境  

Preliminary Study on Special Mineralization Environments of Niujiaotang Cadmium Ore Deposit

作　　者：谷团[1] 

机构地区：[1]中国石油辽河油田公司,辽宁盘锦124010

出　　处：《吉林大学学报（地球科学版）》2017年第2期464-476,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(49633110)~~

摘　　要：牛角塘伴生型镉矿床镉的富集程度高,比克拉克值高4~5个数量级,比工业品位高十几倍至上百倍。早寒武世清虚洞期牛角塘地区处于台缘滩丘环境,在清虚洞组中上部形成了藻丘建造,发育了含藻类、藻球粒、藻鲕粒、核形石和生物碎屑的白云岩,是该矿床最主要的容矿岩性单元。矿体普遍呈似层状、透镜状和脉状产出,矿体产状与容矿围岩的产状基本一致,矿体的分布受清虚洞组藻丘建造以及有利岩性组合的联合控制,具明显的层控、相控、岩控的特点。藻丘建造还可能提供了部分矿源。镉的超常富集、成矿与麻江古油藏的成藏演化具有一定的关系:一是牛角塘矿床成矿年龄为433~510 Ma,即加里东运动的中晚期,而加里东运动中晚期是麻江古油藏的油气活动时期,麻江古油藏的早期演化阶段与牛角塘镉矿的成矿期大体是重合的,成藏应略早于成矿,成矿是在古油藏液态烃仍然存在的情况下进行的,且成矿期有可能一直延伸至油藏被破坏以后;二是油藏流体为成矿提供具还原性质的成矿流体和部分硫源。特殊的岩相古地理环境和古油藏为牛角塘矿床镉的富集和成矿提供了有利条件。The cadmium contents in Niujiaotang associated cadmium ore deposit is five to six orders of magnitude higher than the Clark value,over ten times to near hundred times higher than the industrial grade.In the Qingxudong period of Early Cambrian,the Niujiaotang area was located in the shoal facies of platform margin,which had a set of algal domal in the upper part of the Qingxudong Formation.The dolomite which had algae,algal pellets,oncolites and bioclastic dolomite is the major ore-bearing rock of the Niujiaotang deposit.Ore bodies consistent with surrounding rock are generally stratoid,lenticular and vein-like.The distribution of cadmium ore bodies is jointly controlled by strome algal complex and lithofacies,and obviously controlled by of the strata,lithic facies and rock type.Thealgal domal formation may also provide partial ore source for mineralization.Abnormal enrichment and mineralization of cadmium have certain relationship with the evolution of the Majiang paleo oil reservoir.Firstly,the metallogenic epoch of Niujiaotang deposit is middle to Late Caledonian,from 433 to 510Ma,which is the active period of Majiang ancient oil and gas reservoir.The early stage of evolution is roughly coincident with the mineralization of Niujiaotang cadmium ore depsoit,and the reservoir should be slightly earlier than the mineralization.The mineralization was accompanied by the ancient reservoir under the condition of liquid hydrocarbon,and continued until the reservoir was destroyed.Secondly,the fluid in the Majiang paleo reservoir had provided reductive ore-forming fluid and partial sulfur source.The research results in this paper demonstrate that both paleogeographic environment and paleo reservoir condition had played an important role in the cadmium concentration and mineralization.

关 键 词：成矿环境 古地理环境 麻江古油藏 牛角塘伴生型镉矿床 

分 类 号：P618.81[天文地球—矿床学]