江西冷水坑银铅锌矿床层状矿体的成矿模式及深部勘查方向

A Metallogenic Model for Bedded Orebodies in the Lengshuikeng Ag-Pb-Zn deposit,Jiangxi and Deep Exploration Direction

江西冷水坑矿床层状银铅锌矿体严格受控于晚侏罗世巨厚的火山晶屑凝灰岩内的火山集块-角砾岩夹层,其没有或至少没有发生过大规模的成岩期后热液充填-交代成矿作用,矿体地质特征、矿石结构构造、银矿物标型、与斑岩型矿体的矿化关系,均显示其是陆相火山喷发沉积-成岩成矿的产物,属于火山喷溢矿床类型。矿体经历了火山喷发间歇期岩浆系统的赋矿岩浆聚集→火山活动期赋矿岩浆爆发性喷溢形成含矿火山集块角砾堆积物→在上覆凝灰岩覆盖下形成的封闭环境中成矿物质富集为层状矿体→燕山期含矿花岗斑岩微弱叠加的成矿作用过程。据其成矿过程,提出了针对已有的火山机构,运用探矿工程、地球物理测量,寻找次火山角砾岩筒状矿体和新的火山集块-角砾岩层状矿体的勘查思路。

The bedded ore body in the Lengshuikeng Ag - Pb - Zn deposit, Jiangxi Province is strictly controlled by the middle Jurassic thick volcanic agglomerate within the chip crystal tuff breccia intercalation, which has not undergone a massive wave of hydrothermal filling and metasomatic metallogenesis after its diagenetic stage. Geological characteristics of ore bodies, ore structures, silver mineral typomorphic and mineralization relationship with the porphyry orebodies suggest that it is a product of continental volcanic eruption sedimentary and diagenetic mineralization, belonging to a volcanic eruption deposit type. Its ore-forming processes involve ore-bearing magma accumulation between volcanic eruptions, ore-bearing magma explosive eruption during volcanic activity, formation of ore-bearing volcanic agglomerates and breccia accumulations, new volcanic activity generating overlying big crystal tuff, en- richment of bedded ore bodies in a closed environment, and weak superposition mineralization of granite porphyry in the Yanshan period. According to the ore-forming process and existing volcanic structures, this article suggests a new approach of exploration： using exploration engineering and geophysical measurements to search for volcanic breccia tubular ore bodies, new volcanic agglomerates and breccia bedded ore bodies.