吉尔吉斯斯坦塔尔迪布拉克斑岩型金铜矿床地球化学特征及其意义

塔尔迪布拉克斑岩型金铜矿床位于吉尔吉斯西北部的Kipchak奥陶纪岛弧带,是吉尔吉斯斯坦重要的斑岩型金铜矿床之一。本文在前人研究基础上,对该矿床的地质、地球化学特征进行系统研究。研究结果显示,该矿床斑岩体具有高的SiO_2、Al_2O_3、碱质含量,低的Na_2O、CaO、P_2O_5、Th、Y含量和低Al_2O_3/TiO_2比值,属于典型的钙碱性强过铝质S型花岗岩,是高温条件下发生深熔作用的产物。该矿床轻、重稀土元素分馏明显,相对富集LREE和LILE元素,亏损HFSE元素,其源岩可能为杂砂岩,主要来源于地壳物质。此外,稀土、微量元素特征及其区域构造演化特征均显示,该矿床可能是捷尔斯克伊洋演化末期成熟岛弧环境下岩浆-热液活动的产物。

Geochemical characteristics of the Taldy Bulak porphyry Au-Cu deposit in Kyrgyzstan and its significances

The Taldy Bulak Au-Cu deposit, located in the Kipchak Ordovician island arc belt, northwestern Kyrgyzstan, serves as one of most important porphyry Au-Cu deposits in Kyrgyzstan. Based on previous studies, the geological and geochemical characteristics of this deposit have been systematically studied, and then their geological significances have been discussed in this paper. The results show that the porphyry bodies in this deposit have high SiO2, Al2O3 and alkali contents, as well as low Na2O, CaO, P2O5, Th, Y contents and low Al2O3/TiO2 ratio, belonging to the typical strong peraluminous S-type granites with calc-alkaline, which are the product of anatexis under a high-temperature condition. The porphyry bodies in this deposit have obvious fractionation of LREE and HREE, which are relatively enriched in LREE and LILE while depleted in HFSE, suggesting that their source rocks may be greywacke, primarily originated from the crust material. In addition, the geochemical characteristics of REE and trace elements, as well as regional tectonic evolution demonstrate that this deposit might result from magmatic-hydrothermal activity in a mature island arc environment during the final evolution stage of the Terskey Ocean.