新疆托帕铅锌矿成矿机制及找矿模型

Mineralization Mechanism and Prospecting Model of Tuopa Pb-Zn Deposit in Xinjiang

托帕铅锌矿床是产于塔里木盆地北侧向斜内的典型热卤水沉积—改造型铅锌矿床。在系统野外地质调查及室内综合分析的基础上,详细分析了矿床地球化学及地球物理特征、成矿条件。研究表明:(1)矿床自上而下发育有砂岩型铜矿化、砂砾岩型铜矿化及碳酸盐型铅锌铜矿化,矿体严格受层位控制,呈层状、似层状及透镜状顺层产出;(2)矿体主要赋存于古新统乌拉根组(E_1w^(1～5)),赋矿岩石为一套海侵砂、砾-泥碳酸盐岩建造,岩石粒度与矿化强度呈正相关;(3)金属硫化物具有纹层状、条带状、浸染状及团块构造,偶见铜矿物沿裂隙分布,反映矿床经受早期热卤水喷流及后期构造热液充填叠加改造作用。在上述分析的基础上,对矿区成矿机制进行了研究并对找矿模型进行了构建,认为乌拉根岩性段及向斜/背斜构造活动叠加地段为重点找矿部位。

Tuopa Pb-Zn deposit is the typical thermal-brine sedimentary-reformed Pb-Zn deposit,which is occurred in northern syncline of the Tarim Basin. Based on the detailed field geological survey results and indoor comprehensive analysis results,the geophysical characteristics and geochemical characteristics of the mining area and the metallogenic mechanism are studied. The study results show that：（1）sandstone-type copper mineralization,sandstone-type lead-zinc-copper mineralization and carbonate-type lead-zinc-copper mineralization are developed from up to bottom of Tuopa deposit,the ore-bodies are controlled by strata,they are occurred by stratiform,stratiform-like and lenticular;（2）the ore-bodies are mainly hosted in a set of transgressive sandstone,sandy-argillaceous carbonate build-up in Wulagen Formation of Paleocene（ E_1w^（1～5））,there is a positive correlation between the rock grain size and mineralized intensity;（3）the metal sulfides are characterized by lamellar,banded,impregnated,massive and interstitial structures,which reflects that the deposit is affected by early thermal-brine sedimentation exhalation and later superposition reconstructed by tectonic-hydrothermal fluids. Based on the above analysis results,the metallogenic mechanism of the mining area is discussed and the prospecting model is established,the further study results indicated that the further prospecting work in the mining area should be focused on the Wulagen lithology segment and the tectonic activities superposition area of syncline and anticline.