东昆仑野马泉地区矽卡岩矿床地球化学特征及其成因意义

东昆仑西段(祁曼塔格)的野马泉地区,是青海省内一个重要的多金属成矿区.该区以往的工作程度较低,与花岗岩有关的铁、铜、多金属矿床多是近几年地质大调查中新发现的.本文通过对野马泉地区铁、铜、多金属矿床矿石矿物组合、围岩蚀变分带、黄铁矿Co/Ni比值、矿石稀土元素特征、矿床硫、铅同位素组成特征等的研究.结果表明,野马泉地区矽卡岩型多金属矿床的形成与东昆仑晚古生代-早中生代构造岩浆旋回造山后期的伸展引张环境形成的碱性A型花岗岩有关,成矿物质主要来自岩浆,具有深部来源特征,与幔源基性岩浆底侵及其与壳源酸性岩浆的混合作用有关,属于典型的钙、镁矽卡岩型矿床.

The Geochemical Characteristics and the Meaning of Skarn-Type Deposits in Yemaquan Area,Eastern Kunlun

Yemaquan region in western part of the East Kunlun Range(the Qimantage) is one of the important polymetallogenic districts in Qinghai Province.Many granitoid-related iron,copper and polymetallic deposits and occurrences have newly been discovered during the recent regional geological investigations.This paper studies mineral assemblage,Co/Ni ratios of pyrites,REE and S,Pb isotopic compositions,as well as rock alteration zoning of the iron,copper and polymetallic deposits in Yemaquan region.The results indicate that the skarn-type polymetallogenic deposits in the studied area are related with the alkalic A-type granite,which was formed in lithospheric extensional tectonic setting during the late stage of late Paleozoic-early Mesozoic tectonomagmatic cycle.These deposits of which contains the ore-forming materials with the deep derived characters were mainly from the magma,they are relative to the mixing between underplating mantle-derived basic magma and crust-derived acidic magma,and belong to the typical Ca,Mg skarn-type deposits.