攀西会理县白草钒钛磁铁矿床磁黄铁矿矿物学特征及成因  

Mineralogical characteristics and genesis of pyrrhotite in the Baicao V-Ti magnetite deposit in the Huili area of the Panzhihua-Xichang Rift

作　　者：邱红信 张贵山[1,2] 温汉捷 彭仁 孟乾坤[1] 李石磊 QIU Hong-xin;ZHANG Gui-shan;WEN Han-jie;PENG Ren;MENG Qian-kun;LI Shi-lei(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;Mining Corporation of Chuanwei Group,Chengdu 610059,China)

机构地区：[1]长安大学地球科学与资源学院,陕西西安710065 [2]自然资源部岩浆作用成矿与找矿重点实验室,陕西西安710065 [3]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550081 [4]川威集团矿业总公司,四川成都610059

出　　处：《矿物学报》2021年第3期245-257,共13页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(编号:41073027);中央高校基本科研业务费专项资金(编号:310827172003);陕西省自然科学基础研究计划项目(编号:2019JM-161);财通矿山新兴关键矿产资源综合研究项目(编号:030216190040)。

摘　　要：攀西会理县白草矿区以钒钛磁铁矿而闻名,但该钒钛磁铁矿床中还发育一定规模的富钴硫化物矿石,对该类型矿石的形成机制研究还不深入。本文选择白草矿区产出的浸染状、致密块状、网脉状和斑杂状富钴硫化物矿石中的磁黄铁矿做为研究对象,在野外地质调查的基础上,通过矿相学和电子探针等方法对磁黄铁矿的成分和晶体类型进行研究。利用磁性胶体可以鉴别磁黄铁矿晶体类型的原理,确定了研究区的磁黄铁矿具有单斜磁黄铁矿(Mpo)和六方磁黄铁矿(Hpo)两种晶体类型,厘定了细脉状、叶片状和不规则状交生体。通过研究磁黄铁矿中各主量元素特征,计算了磁黄铁矿形成温度、硫逸度和M/S值等参数。将磁黄铁矿形成划分岩浆成矿期(熔离阶段、接触交代阶段)和热液成矿期,并初步厘定了4类磁黄铁矿生成顺序:首先形成浸染状矿石磁黄铁矿与致密块状矿石磁黄铁矿,其次形成斑杂状矿石磁黄铁矿,最后形成网脉状矿石磁黄铁矿。The Baicao deposit in the Huili area of the Panzhihua-Xichang Rift is famous for its V-Ti magnetite mineralization. However, it has a certain amount of the cobalt-rich sulfide ore whose formation mechanism was not deeply studied yet. In this paper, the pyrrhotite from disseminated, dense massive, stockwork veining, and spotted cobalt-rich sulfide ores in the deposit is taken as the research object. On the basis of field geological survey, the compositions and crystal types of pyrrhotites have been studied by using means of mineralography and electron microprobe. Based on the principle that magnetic colloid can be used to identify crystal types of pyrrhotites, it is determined that there are two crystal types of pyrrhotites, including monoclinic pyrrhotite(Mpo) and hexagonal pyrrhotite(Hpo) which were intergrown with each other in forms of veinlet, leaf and irregular shape. The formation temperature, sulfur fugacity and M/S value of pyrrhotites were calculated based on the study of characteristics of major elements in pyrrhotites. The formation of pyrrhotite can be divided into the magmatic metallogenic period(sulfide segregation stage, contact metasomatic stage) and hydrothermal metallogenic period. The sequence of four types of pyrrhotites is preliminarily determined in following order form the first of disseminated pyrrhotite and massive pyrrhotite, to the second of variegated pyrrhotite, and to the last of stockwork veining pyrrhotite.

关 键 词：磁黄铁矿 矿物学特征 矿石成因 白草矿区 

分 类 号：P571[天文地球—矿物学]