新疆阿尔泰山系南缘萨尔朔克金铜多金属矿床地球化学特征与矿床成因探讨

新疆阿尔泰山系南缘萨尔朔克金铜多金属矿床产于中泥盆统阿舍勒组上亚组的中酸性火山岩-次火山岩中,围岩为流纹斑岩。地表及浅部以金铜矿化为主,向深部金铜矿化逐渐减弱而铅锌矿化增强。矿化受地层层位控制明显。笔者通过矿区详细的野外地质调查、矿石与不同类型岩石围岩的稀土、微量元素地球化学对比研究,表明铜矿石、铅锌矿石与矿化流纹斑岩以及流纹斑岩的稀土元素、微量元素分布型式相似,均属明显右倾、轻稀土富集、强负Eu异常;且富集Ba、U、Zr、Hf、Ti而相对亏损Th、Sr、Sm等元素;结合矿床地质特征,认为萨尔朔克金铜多金属矿床为海相火山-次火山热液矿床,金铜、铅锌矿化与流纹斑岩密切相关,流纹斑岩为该矿床矿化提供重要成矿物质来源。辉绿岩的稀土及微量元素分布型式均呈平坦式,明显不同于矿石及其他围岩岩石类型,表明辉绿岩可能是成矿后的深部地幔岩浆侵入结晶的产物。

Geochemical Characteristics and Genetic Discussion of the Saersoc Au-Cu Polymetallic Deposits in Southern Margin of Altay Mountains,Xinjiang

Located at the southern margin of Altay mountain syctem, the Sarshoke gold-copper polymetallic deposit is occurred in medium-acidic volcanic-subvolcanic rocks of the upper subgroup of Middle-Aevonian Ashele Group. The wall rocks of this deposit are rhyolite porphyries. The surface and shallow depth are shown by Au-Cu mineralization, while toward the depth, Au-Cu mineralization is gradually weakened and Pb-Zn mineralization is greatly increased, being evidently controlled by stratigraphic horizon. Based on the detailed geological field survey and geochemical comparative study on REE and trace elements of ores, different types of wallrocks, it shows that the REE and trace elements' distribution patterns of Cu and Pb-Zn ores and mineralized rhyolite porphyries are much similar to that of rhyolite porphyries, all of which appears apparently rightward decline, rich in LREE, intensive negative Eu abnormality, enrichment in Ba, U, Zr, Hf and Ti, while decrement in Th, Sr, Sm. Combined with geological characteristics of this deposit, it figures that the Saersoc Au-Cu polymetallic deposit belongs to the type of marine volcanic or subvolcanic hydrothermal deposit, whose Au-Cu and Pb-Zn mineralization is closely related to rhyolite porphyries, which has provide vital sources of metallogenic matter. The dolerite is much unlikely to ores or other types of wallrocks in REE and trace elements distribution patterns, illustrating that the dolerite was possibly result of crystallization and invading of mantle magma from the deep.