Lead isotopic composition and lead source of the Mengentaolegai Ag Pb Zn In deposit in Inner Mongolia
ZHANG Qian, ZHAN Xin zhi, QIU Yu zhuo, SHAO Shu xun, LIU Zhi hao(Open Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China)
Mengentaolegai deposit is occurred in the center of the Hercynian granite batholith which consists of biotite plagioclase granite and muscovite plagioclase granite. The vein type ore bodies are controlled by the east west trend faults. The main useful constituents of the deposit are Pb, Zn, Cu, Ag associated with Sn, In, Ga and Cd, etc. Lead isotopic composition of the ore is different from those of the ore hosted Hercynian granite and the Yanshaniangranite outside the ore region. Lead of the ore is neither derived from the magmatism nor from the reformation of these granite rocks. There are two probable sources of the ore lead. One is the mantle magmatism. It is possible that there is a mantle source magmatic rock in depth of the ore region. Another source is the Precambrian basement metamorphic rocks in the region.