云南六苴砂岩型铜矿床含矿层岩石地球化学与矿石矿物学研究

【作者】 李静；

【导师】 吴静； 韩润生；

【作者基本信息】 昆明理工大学 ， 地球化学， 2010， 硕士

【摘要】 论文在“西南地区层控型多金属矿床成矿规律总结研究”等项目资助下完成。采用地球化学、电子探针等方法研究六苴砂岩型铜矿床六苴段含铜砂岩的岩石化学与矿石矿物学特征。取得以下认识：1、采用Cu-S体系相图与电子探针分析相结合的方法,估算了六苴铜矿床成矿温度为72±3℃—103.5±0.5℃。反映了六苴铜矿床主要在沉积-成岩期的低温热液条下件形成。2、根据电子探针分析计算,得到矿物分子式为Cu1.96S,该矿物为久辉铜矿(djurleite),在六苴铜矿区尚属首次描述。3、对六苴中亚段(K2ml2)含铜砂岩进行了地球化学研究,结合下亚段(K2ml1)地球化学特征,认为六苴段含铜砂岩Mo、Cd、As、Cu、Ag、Hg等亲硫元素富集,具“矿源层”特征。从铜矿石→浅色矿化砂岩→浅色无矿砂岩,随着铜含量降低,Mo、Cd、As、Hg平均含量逐渐降低,ΣREE与高场强元素Nb、Zr、Hf、Th平均含量逐渐升高。这一特征显示砂岩中铜的富集过程与强烈的水—岩作用有关,六苴铜矿床铜矿物的形成、富集与热液活动密切相关。4、辉铜矿不仅仅存在于浅色砂岩中,在紫灰色砂岩中也存在。砂岩因氧化作用由浅变紫,该过程中伴随Cu2+迁移,为Cu的聚集提供了条件。5、总结了矿体中矿石矿物组合水平分带和元素组合分带规律：矿体东界具砷黝铜矿—方铅矿—闪锌矿—黄铁矿组合,元素组合为Cu-Pb-Zn-Sb-Hg；矿体中心位置具赤铁矿—辉铜矿—斑铜矿组合,元素组合为Cu-Ag-Sb-Hg。金属矿物交代关系为：赤铁矿交代辉铜矿,辉铜矿交代斑铜矿,斑铜矿交代黄铜矿,黄铜矿交代黄铁矿。这一规律为矿床成因研究提供了重要依据。更多还原

【Abstract】 Sponsored by the national project for crisis mine named"Study on metallogenic regularity of strata bound type polymetallic ore deposit in Southwest China"etc, on the basis of Geochemistry and Electron Probe Microscopic Analyzer (EPMA), this thesis studies on the Petrochemistry and Ore mineralogy characteristics in the Liuju copper deposit. The main understanding and conclusions are as follows:1. Based on the method combining Cu-S system phase diagram with EPMA, It drew the estimation that the ore-forming temperature is about 72±3℃—103.5±0.5℃. It is reflect that the deposit is mainly formed in sedimentary-diagenetic period by the low-temperature hydrothermal metasomatism.2. It is the first time to describe djurleite in this area.3. Geochemistry characteristics of K2ml1 and K2ml2 show that, the chalcophile elements Mo, Cd, As, Cu, Ag and Hg enriched in the sandstone, it have the characteristics of ore source bed. From the copper ore to gray sandstone, to purple sandstone, with the average values of Cu reduced,EE and high field strength elements (Nb、Zr、Hf、Th) increased gradually. Trace elements in grey sandstone are remarkable different from purple one. It indicates that the copper ore formed by water-rock interaction and are closely related with hydrothermal activity.4. The chalcocite not only exists in grey sandstone, but also in grey-purple. The sandstone get reddening by oxidation, and Cu2+ migration happening.5. It sums up some rules on horizontal zoning of ore mineral association and zoning of element association in ore body:In the eastern part of ore body, the mineral association is tennantite, galenite, pyrite and sphalerite, and element association is Cu-Pb-Zn-Sb-Hg; In the middle of ore body, the mineral association is hematite, chalcocite and bornite, and element association is Cu-Ag-Sb-Hg. The sequence of mineral metasomatic evolution is pyrite→chalcopyrite→bornite→chalcocite→hematite. This rule provides a basis for metallogenic theory更多还原