摘要
攀西红格钒钛磁铁矿矿田白草矿区发育富钴硫化物矿物,关于其成因和形成环境方面的研究较为薄弱。本文采用矿物学、矿物化学、地球化学等方法对其进行系统研究。矿石中主要富钴硫化物为磁黄铁矿(Po)、黄铁矿(Py)、镍黄铁矿(Pn)、硫钴镍矿(Se)。磁黄铁矿Co、Ni平均质量分数分别为0.21%、0.42%,Co/Ni平均值为1.10;黄铁矿Co、Ni平均质量分数分别为0.18%、0.29%,Co/Ni平均值为0.77;镍黄铁矿Co、Ni平均质量分数分别为2.67%、34.30%,Ni/Fe平均值为1.08、S/Fe平均值为1.91、M/S^(#)平均值为1.13;硫钴镍矿Co、Ni平均质量分数分别为24.30%、22.90%,Co/Ni平均值为1.06。根据Po-Py矿物温度计,白草矿区富钴硫化物结晶温度在267~490℃之间,表明其形成于中高温的条件。通过与地幔包体镍黄铁矿S/Fe、M/S^(#)特征值的对比,结合磁黄铁矿具有陨硫铁(Tr)同质多象晶体的特征,认为白草矿区硫化物具有地幔源的特征,说明成矿物质来源于地幔。白草矿区钴地球化学特征研究表明,在硫化物熔体分离过程中,钴迁移至单硫化物固溶体形成Po-Py固溶体,再由Po-Py固溶体中迁移至Pn、Se,形成了Se、Pn、Po-Py、Ccp(黄铜矿)中Co质量分数依次递减的现象。
Cobalt rich sulfide minerals are developed in Baicao mining area of Hongge ore field in Panxi. The research on their genesis and formation environment is relatively weak. In this paper, the mineralogy and mineral chemistry are used for a systematic study. The results show that the main cobalt-rich sulfides in the ore are pyrrhotite, pyrite, pentlandite, and siegenite. The average contents of Co and Ni in pyrrhotite are 0.21% and 0.42% respectively, and the average value of Co/Ni is 1.10;The average contents of Co and Ni in pyrite are 0.18% and 0.29% respectively, and the average value of Co/Ni is 0.77;The average contents of Co and Ni in pentlandite are 2.67% and 34.30% respectively, and the average value of Ni/Fe, S/Fe and M/S^(#)are 1.08,1.91 and 1.13 respectively;The average contents of Co and Ni in siegenite are 24.30% and 22.90% respectively, and the average value of Co/Ni is 1.06. According to the pyrrhotite-pyrite mineral thermometer, the crystallization temperature of the Baicao cobalt rich sulfide is about 267-490 ℃, which indicates that it was formed at medium high temperature. Compared with the characteristic values of S/Fe and M/S^(#)of the mantle xenolith pentlandite, the pyrrhotite has the characteristics of troilite(Tr) homomorphic polycrystal, which reflects that the ore-forming materials were derived from the mantle. The geochemical characteristics of cobalt in Baicao mining area show that in the process of sulfide melt separation, cobalt migrated to mono-sulfide solid solution to form Po-Py solid solution, and then migrated further to form Pn and Se solid solution, forming the phenomenon that the content of Co in Se, Pn, Po-Py and Ccp decreases gradually.
作者
张贵山
邱红信
温汉捷
彭仁
孟乾坤
Zhang Guishan;Qiu Hongxin;Wen Hanjie;Peng Ren;Meng Qiankun(School of Earth Science and Resources,Chang’an University,Xi’an 710065,China;Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits,Ministry of Natural Resources,Xi’an 710065,China;State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China)
出处
《吉林大学学报（地球科学版）》
CAS
CSCD
北大核心
2021年第6期1740-1752,共13页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(41073027)
中央高校基本科研业务费专项资金(310827172003)
陕西省自然科学基金项目(2019JM-161)
财通矿山新兴关键矿产资源综合研究项目(030216190040)。
