摘要
康滇地轴中段攀枝花大田地区石墨矿赋存于古元古界康定群变质岩层中,含矿岩性为黑云斜长片麻岩及混合岩化黑云斜长片麻岩,矿体呈层状、似层状。薄片鉴定石墨呈鳞片状,大鳞片石墨(>100目或>0.147mm)占比76.69%。主量元素分析矿段SiO_(2)含量比非矿段平均高14.73%,反映含矿段原岩石英含量更高。碳同位素分析δ^(13)C值在-19.5‰~-21.9‰之间,平均值-20.73‰,指示石墨为有机碳成因。赋矿岩石原岩恢复为一套富含有机质的沉积碎屑岩。认为大田石墨矿床属有机成因的区域变质型大鳞片晶质石墨矿,混合岩化作用有利于石墨片径增大。
Located in the middle part of the Kang-Dian axis,the graphite deposits in Datian area of Panzhihua are hosted in the metamorphic strata of Paleoproterozoic Kangding Group.Investigation reveals that the ore-bearing lithology is biotite plagioclase gneiss and migmatized biotite plagioclase gneiss,and the ore bodies are stratified or stratiform-like in nature.Under the microscope,the graphite occurs as flaky shape and large flaky graphite(>100mesh or>0.147mm)accounts for 76.69%.Major element analysis shows that the SiO_(2)content of ore section is 14.73%higher than that of non-ore section on average,which reflects that the quartz content of original rock is higher in ore-bearing section.Theδ^(13)C value of carbon isotope analysis ranges from-19.5‰to-21.9‰,with an average value of-20.73‰,indicating that graphite is of organic carbon origin.Restoration of the ore-bearing protolith shows that it was a set of sedimentary clastic rocks rich in organic matter.It is concluded that the Datian graphite deposit belongs to the regional large scale metamorphic crystalline graphite deposit with organic origin.The migmatization of protolith is conducive to the increase of graphite flake diameter.
作者
冯光兴
姚建
王凤岗
吴玉
陈友良
徐争启
陈志国
Feng Guangxing;Yao Jian;Wang Fenggang;Wu Yu;Chen Youliang;Xu Zhengqi;Chen Zhiguo(NO.280 Research Institute,China National Nuclear Corporation,Guanghan,Sichuan 618300,China;Beijing Research Institute of Uranium Geology,China National Nuclear Corporation,Beijing 100029,China;Chengdu University of Technology,Chengdu,Sichuan 610059,China)
出处
《矿物岩石》
CAS
CSCD
北大核心
2022年第3期48-57,共10页
Mineralogy and Petrology
基金
国家自然科学基金项目(批准号:42072096)
中国核工业地质局中央财政地勘费项目“康滇地轴攀枝花—武定地区铀矿资源调查评价”(项目编号:202112)
“康滇地轴富大铀矿成矿环境及战略选区研究”(项目编号:202137-3)。
关键词
大田石墨矿床
碳同位素
混合岩化
矿床成因
康滇地轴
Datian graphite ore
carbon isotope
migmatization
origin of deposit
Kang-Dian axis
