金川铜镍矿床中断裂系统的形成演化及对矿体的控制

曾认宇^{1, 2}，赖健清^{1, 2}，毛先成^{1, 2}，陶斤金^{1, 2}

(1. 中南大学 有色金属成矿预测教育部重点实验室，长沙 410083；
2. 中南大学 地球科学与信息物理学院，长沙 410083)

摘 要：金川铜镍硫化物矿床位于华北板块西南缘的龙首山隆起带内，断裂系统是其主要的控矿因素，在多次构造运动中，形成了纵横交错的断裂，其运动也有多期性，根据目前断裂性质，分为4组，分别为：北西向压性断裂，北西向容纳金川岩体的断裂，北东东向扭性断裂和北东向张性断裂。其中前两组在岩体侵入前已经存在，为金川岩体提供了成矿通道和成矿空间，而后期被改造；后两组为成矿后断裂，改造了矿床的原始形态。通过微量元素和前人年代学研究，认为其主要形成于中元古代大陆拉张环境下的龙首山裂谷张开初期。成矿前区域处于古陆核边缘的挤压环境，成矿期为被动大陆边缘的拉张裂谷环境，成矿后变为活动大陆边缘的挤压环境。通过恢复其原始产状发现容矿断裂成右列式的雁列形态展布，根据后期改造的特点，推测在Ⅲ矿区与F₁断层间、Ⅳ矿区的东南部的第四系覆盖层下，是找矿的有利靶区。

关键词：金川铜镍硫化物矿床；矿体原始形态；断裂系统；矿体改造；成矿预测

Evolution of fault system and its controlling on Jinchuan Cu-Ni (PGE) sulfide deposit

ZENG Ren-yu^{1, 2}, LAI Jian-qing^{1, 2}, MAO Xian-cheng^{1, 2}, TAO Jin-jin^{1, 2}

(1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China)

Abstract:The Jinchuan Cu-Ni (PGE) sulfide deposit is located in the Longshou Mountain, southwestern margin of North China plate. The fault system is the main ore-controlling factor. During numbers of periodic tectonic movements, the criss-cross faults formed. According to the fault properties, these faults can be divided into four categories as: Northwestern compression fault, Northwestern fault which accommodates the Jinchuan intrusion, Northeastern sheer fault, and Northeastern tension fault. The former two groups formed before intrusive bodies are emplaced. These faults provide Jinchuan intrusion with metallogenic conduction and space, which were transformed at the later stage. The latter two groups belong to post-metallogenic faults, and transform the original form of deposit. Through the study of trace elements and geochronology, it could be found out that the deposit formed in the primer period of Longshou Valley’s fissuration at an atmosphere of Mesoproterozoic continental tentional zone. This area has experienced various kinds of environment, which are as follows: the crushing environment of craton in pre-ore stage, the extensional rift environment of passive continental margin in ore stage, and the crushing environment of active continental margin in post-ore stage. By restoring the original form, it shows that the ore-controlling faults crack into en-echelon. According to the properties of the late-reformation, it is estimated that there exist several favorable areas for ore-prospecting, including the region between mining area III and F1, and the district under the Quaternary strata, which is in SE of IV mining area.

Key words:Jinchuan Cu-Ni (PGE) sulfide deposit; orebody original form; fault system; orebody transformation; metallogenic prognosis