江西红山斑岩型铜矿床成矿构造背景探讨

The Metallogenic Tectonic Background of Hongshan Porphyry Copper Deposit

红山铜矿地处武夷山褶皱隆起带南段瑞金-寻乌北北东向断裂带、上杭-云霄北西向断裂带和会昌环形构造的交汇处。通过红山斑岩型矿床成岩、成矿地质条件分析,认为区内燕山晚期的构造以水平拉张为主应力方向,构造形迹以张性断裂和滑脱构造为主要形式。拉张性质的构造有利于花岗闪长斑岩体侵入、定位,隐爆角砾岩是该区花岗闪长斑岩演化后期的特定产物。红山铜矿花岗闪长斑岩的主要造岩矿物QPA图解和地球化学主量元素成岩构造环境判别图解反映,红山斑岩型矿床的成岩、成矿属于陆内造山后的拉张构造环境。根据以上特点得出红山铜矿可能是在燕山晚期大陆板块陆内裂解、拉张构造背景下成矿的结论。

Hongshan copper deposit is located in the intersection of Ruijin-Xunwu North-North-East fault belt, Shanghang-Yunxiao North-West fault belt and Huichang Circular Structure. Through analysizing rock and porphyry deposit, ore-forming geological conditions, this paper suggests that the major stress direction of the geological structure is horizontal tensile. The geological structures have the characteristics of extensional fracture and detachment structure. The tensile properties of structure is conducive to the body of granodiorite porphyry intrusion and positioning. Hydrothermal breccia is the specific product of the evolution of granodiorite porphyry deposit. QPA illustrations of major rock-forming minerals and diagenetic tectonic discrimination geochemistry diagrams of major elements show that, diagenetic mineralization of Hongshan porphyry deposits belongs to Extensional setting upon orogeny. The above characteristics testify that the continental plates＇ land cracking and tensile structure lead to the mineralization of Hongshan Copper Mine in the latter stage of Yanshan period.