青海卡尔却卡铜矿床地质与地球化学特征

Geological and geochemical characteristics of Kaerqueka copper deposit in Qinghai

卡尔却卡铜矿床所属的东昆仑地区是当前成矿研究的热点区域,前人对该地区做了大量的成矿学与构造学研究.文章通过对矿床矿石的标本观察,偏光显微镜观察,能谱面扫描分析,等离子体质谱仪分析等,对卡尔却卡矿床围岩的蚀变、化学元素、微量元素和矿石的矿物特征、化学元素、微量元素进行研究.发现围岩与矿石中LREE/HREE值为3.96 ～5.26与0.493 ～0.999;强不相容元素Rb、Ba、Cs等明显亏损,Cr、Nb等中等不相容元素亏损弱,呈负Eu异常;卡尔却卡铜矿床围岩的Rb低,Sr含量值均较高,Rb/Sr值及^87Rb^86Sr、^87Sr^86Sr）i值均较高.综合分析认为该地区成矿物质来源于下地壳或上地幔等深部环境,矿床的形成经历了多次不同环境、不同性质成矿作用的改造叠加,矿床类型为改造层控型的夕卡岩矿床.

The Eastern Kunlun area, where the Kaerqueka copper deposit is located, has been the focus area for the metallogenic study and exploration. The authors carried out the study on country rock alteration, chemical and trace elements, and mineral characteristics of the deposit through methods of mineral specimen observation, polarized light microscope observation, EDS analysis and Plasma mass spectrometer analysis etc.. It is found that the ratio of LREE/HREE in the country rock and ore is （3.96 - 5.26）/ （0. 493 - 0. 999）. The strong incompatible elements of Rb, Ba, Cs and others have obvious deficit, while the medium incompatible elements of Cr, Nb have weak deficit, and the REE is characterized with negative Eu anomaly. In the country rock, the concentration of Rb element is high but low Sr value. The ratios of Rb/Sr, ^87Sr/^86Sr are all high. Based on the above - mentioned comprehensive analysis, the metallogenic material source in the deposit area mainly comes from the deep environment such as lower crust or upper mantle et al, and the formation of the deposit has experienced with multi stages reformation and overprinting process by different types of mineralization in the different environments. Therefore, the Kaerqueka copper deposit type is classified into the stratabound - reformed skarn type copper deposit.