贵州广龙坡铅锌矿地质特征及成矿机理分析

Geological characteristics and metallogenic mechanism of Guanglongpo lead-zinc deposit,Guizhou

文章从广龙坡铅锌矿地质特征出发,对广龙坡铅锌矿及其所在的湘黔铅锌矿带上铅锌矿的成矿机理进行了分析。成矿经历了沉积和改造两个阶段,沉积发生在早寒武世的浅水潮下斜坡相环境,主要形成硫源层;改造主要发生在早奥陶世和早志留世,中低温区域热液流体主要提供铅、锌物源。还原硫对铅、锌物源具有捕获功能而成矿,故铅锌矿仅赋存在藻礁灰岩之中,因其上缺乏盖层,故矿石品位总体偏低。区域内地层中铅、锌元素背景值偏高。矿床成因为沉积改造型中—低温热液矿床,为典型的MVT型矿床。

Based on study of geological characteristics of Guanglongpo lead-zinc deposit, the metallogenic mechanism of the de- posit as well as other lead-zinc deposits in the Hunan-Guizhou lead-zinc metallogenic belt were analyzed. The lead-zinc mineraliza- tion process experienced two stages, i.e., sedimental deposition and transformation. Sedimentary deposition occured in the early Cam- brian shallow tidal facies environment mainly resulted in the formation of sulfur source layer. Transformation mainly occurred in the ear- ly Ordovician and early Silurian periods, the medium-low temperature hydrothermal fluid mainly provided lead and zinc sources. Then the lead-zinc source materials were captured by the reductive sulfur to form the lead-zinc orebody. Therefore the lead-zinc orebody oc- curs only in the algal reef limestone. Due to lacking of cover layer, the lead-zinc ore grade is generally low but the background concen- tration of lead and zinc in the region strata is relatively high. The deposit genesis belongs to medium-low temperature hydrothermal sendimentary transformation type lead-zinc deposit, which is a typical MVT deposit.