西藏洞中拉铅锌矿床成因探讨

DISCUSSION ON THE GENESIS OF THE DONG ZHONGLA LEAD-ZINC DEPOSIT,TIBET

洞中拉铅锌矿床是冈底斯中东段念青唐古拉中生代岛链隆起带,及色日绒-巴嘎弧内裂谷带中重要矿床.初步总结了矿床形成机制,认为矿化得益于多期多阶段岩浆活动,晚燕山早期中酸性岩体上侵贯入与碳酸盐岩接触交代形成早期矽卡岩.经多次构造改造,矿区岩浆岩、地层发生大规模构造变形,形成近SE向的"M"型同斜倒转褶皱.后期热液沿褶皱轴面劈理贯入,在裂隙及转折端虚脱部位富集成矿,矿区碳质板岩起到很好屏蔽效应.洞中拉矿床为典型矽卡岩型铅锌矿床,提出新的成矿模式,认为矿区找矿重点在矿区中东段.

The Dong ZhongLa Lead-zinc deposit, is the important deposit in Mesozoic Nyanq6ntanglha island chain in middle east of Mount Kailash and in Se Ri Rong - Ba Ga arc rift belt.This paper summarized the initial deposit formation mechanism,considering the mineralization stage benefits from several metallogenic stages magma activities,late yanshan early intermediate-acidic rock rising and injection ,then hapend contact metasomatism with carbonatite,forming the early stage skarn,after several tectonic reworking,magmaticrock of ore field.The stratum happened massive tectonic deformation,forming type of＂M＂non-overturned fold with almost south-east of trend,later the hydrothermal solution injects again along with the axial plane cleavage of fold,about the ore enrichment in fracture and the turning of loose part,carbonaceous slate of diggings have a very good effect of shield.The Dong ZhongLa deposit is the typical type of skarn and Lead-zinc deposit.this paper raise a new metallogenic model,regarding as the key point of ore prospecting in middle east of diggings where has no undertaking to work until now, has reference value for ore-prospecting survey in this diggings.