从锡矿山矿田的古流障系统看锡矿山锑矿深边部的找矿方向

陈星霖^{1, 2}，吴延之^{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：通过分析14个矿床矿化点的分布资料，编制锡矿山锑矿田古成矿环境网络示意图，总结锡矿山锑矿床的14项基本成矿特点，归纳分析前人对本区锑矿成因的5种观点和相关依据，提出锡矿山矿田古环境系统，深-流-障，即深流-环流-障积成矿系统的新认识。湘中晚古生代台内断陷盆地是成矿环境系统的重要地质基础，由西向东NE向5条深切基底的断裂构成断陷盆地的成矿环境主干，而以冷水江大断裂及其分支75号断裂表现尤为突出。锡矿山矿田构造展布、蚀变矿化、包体分析、化探异常，表明它们间存在叠合和耦合关系，并显示出矿田内存在一个由南西向北东，并有多处分支分叉的环境系统。矿田内众多矿体分布表明NE向主断裂带、F₇₅及其3条分支断裂带与棋梓桥组、佘田桥组、刘家塘组3个层顶界面处为成矿的有利空间，而以佘田桥组顶界处规模最大，连续性最好，组成了完整的障积组合系统。盆地周边侵入岩体和深部可能的地幔柱，是盆内的主要热源，上升热矿水与下渗水的长期环流是盆地内成矿作用重要动力机制，分析并剔除了3种环流(垂向环流、双向环流、洞穴环流)的方式和机制。总结了鉴别古成矿环境系统的4大标志。针对矿田成矿系统环流分布特点，提交了马月山背斜至陈家排的6处有利找矿靶区。

关键词：锡矿山矿田；古成矿环境系统；深边部找矿

Prospecting direction on deep and side prospecting of Xikuangshan antimony deposit based on ancient flow block system of ore-field

CHEN Xing-lin^{1, 2}, WU Yan-zhi^{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:According to the distribution data of 14 mineralization points, the sketch map of the ancient ore-forming environment in Xikuangshan antimony ore-field was drawn, 14 basic mineralization characteristics in this area were summarized, and the previous 5 kinds of viewpoints on genesis as well as its relevant basis were analyzed. Through the above comprehensive analysis, the paleoenvironmental system of the Xikuangshan ore-field, deep-flow-barrier, namely the new understanding of flow-circulation-bafflestone metallogenic system was proposed. The late Paleozoic rift basin, which is inside the platform of central Hunan, is a significant geological basis of the metallogenic environment system. In this mining area, from west to east, there exist 5 NE trending faults, which deeply ingrow into the basement, constitute the backbone of the metallogenic environment. Among these faults, the Lengshuijiang fault and its branch No.75 fault are particularly prominent. In Xikuangshan ore-field, by the analysis of the structural distribution, mineralization and alteration, inclusion and the geochemical anomaly, it can be concluded that there exists a superposition and coupling relationship between them, thus demonstrating that there is a environment system extending from SW to NE with various branches of bifurcation. According to the distribution of the numerous mineral deposits, it can be concluded that the favorable space for mineralization is the top layer interface between the NE-trending main fault zone, F75 as well as its three branches and the three groups of Qiziqiao formation, Shetianqiao formation and Liujiatang formation. In addition, with the largest top boundary and the best continuity, the Shetianqiao formation composes a complete bafflestone combined system. The intrusive rocks around the basin and the deep mantle plume are possibly the main heat source. What’s more, the uprising thermal water and the infiltration water are the important driving force in the basin mineralization mechanism. Through analysis, three kinds of modes and mechanisms i.e., the circulation-vertical circulation, two-way circulation and the cave circulation, were analyzed and removed. Also, four signs for the identification of ancient metallogenic environment system were summed up. According to the distribution characteristics of the metallogenic circulation system, the six areas of favorable prospecting targets from Mayue mountain antiline to Chenjiapai were put forward.

Key words:Xikuangshan ore-field; ancient metallogenic environment system; deep and side prospecting