四川沐川地区下三叠统飞仙关组底部的沉积型铜矿含矿岩系特征及其对物源区的制约  

CHARACTERISTICS OF SEDIMENTARY COPPER-BEARING ROCK SERIES AT THE BOTTOM OF LOWER TRIASSIC FEIXIANGUAN FORMATION IN MUCHUAN AREA OF SICHUAN PROVINCE AND CONSTRAIN ON PROVENANCE AREA

作　　者：张航飞 赵俊兴[3] 文俊 韩晓影 钟强生 竹合林 梁成 ZHANG Hangfei;ZHAO Junxing;WEN Jun;HAN Xiaoying;ZHONG Qiangsheng;ZHU Helin;LIANG Cheng(The 7^(th)Geological Brigade of Sichuan,Leshan,Sichuan 614000,China;Zhang Jinyuan Model Innovation Studio,Leshan,Sichuan 614000,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;College of Mining Engineering,North China University of Science and Technology,Tangshan,Hebei 063210,China)

机构地区：[1]四川省第七地质大队,四川乐山614000 [2]张金元劳模创新工作室,四川乐山614000 [3]成都理工大学沉积地质研究院,四川成都610059 [4]华北理工大学矿业工程学院,河北唐山063210

出　　处：《矿物岩石》2023年第2期58-68,共11页Mineralogy and Petrology

基　　金：四川省自然资源厅2020年省政府性投资地质勘查项目(编号:DZ202002);四川省自然资源厅科技项目(编号:kj-2022-6);四川省地质矿产勘查开发局张金元劳模创新工作室科技项目(编号:207队科技-2022-2号)。

摘　　要：目前关于赋存P/T界面之上的沉积型铜矿的报道很少,采集四川沐川地区下三叠统飞仙关组底部的碎屑岩样品进行地球化学、岩矿鉴定等测试分析,探讨了铜矿含矿岩系特征及其物质来源。结果表明,区内铜矿呈层状产于下三叠统飞仙关组底部的灰绿色砂页岩层,矿石矿物主要为辉铜矿、斑铜矿和黄铜矿。研究区碎屑岩样品具有富Fe,Mg而SiO_(2)含量较低的特征,样品的Sc,Cr和Co等亲铁镁矿物元素的含量皆高于上地壳的平均值;La_(N)/Yb_(N)比值介于8.07~12.37,属于轻稀土富集;δEu值介于0.80~1.03,显示弱的Eu负异常;δCe值介于0.97~1.03,没有明显的Ce异常。根据岩性岩相特征和物源分析结果,认为含铜矿岩系主要由初次循环的沉积物组成,主要来源于康滇古陆上的峨眉山玄武岩,区内铜主要富集于含粉砂质条带黏土岩和含泥质条带粉砂岩等潮坪相岩石中,其改造成矿作用不明显,属于同生-成岩阶段产物。At present,there have been few reports on the occurrence of depositional copper deposits on the Permian/Triassic interface.In this paper,the detrital rock samples from the bottom of the Lower Triassic Feixianguan Formation in Muchuan area of Sichuan Province are tested and analyzed by means of geochemistry,rock and ore identification,aiming to unravel the characteristics of ore-bearing rock series and material sources of copper deposits.The results show that the copper deposits are stratified in the gray-green sand shale at the bottom of the Lower Triassic Feixianguan Formation,and the ore minerals are mainly chalcocite,bornite and chalcopyrite.Geochemical analysis reveals that the clastic rock samples in the study area are rich in Fe and Mg,but low in SiO_(2) content.The contents of Sc,Cr and Co are higher than the average value of the upper crust.La_(N)/Yb_(N) ratio of the clastic rock samples is 8.07 to 12.37,belonging to the light rare earth enrichment.The δEu values range from 0.80 to 1.03,with a weak negative Eu anomaly and the δCe values range from 0.97 to 1.03,with no significant Ce anomaly.According to the lithologic lithofacies characteristics and provenance analysis results,the Lower Triassic Feixianguan copper-bearing rock series in Muchuan area is mainly composed of the initial circulation of sediments which are primarily derived from the Mount Emei basalt in Kangdian axis.Copper in Muchuan area is mainly occurred and enriched in the tidal flat rocks such as silty banded clay rocks and argillaceous banded siltstone,with inconspicuous transformation mineralization.It is considered that the copper deposits in this area belong to syngenetic and diagenetic stage mineralization products.

关 键 词：下三叠统飞仙关组 沉积型铜矿 物源 四川沐川 

分 类 号：P579[天文地球—矿物学] P611[天文地球—地质学]