江西相山矿田深部多金属矿化特征

Characteristics of Deep Polymetallic Mineralization in the Xiangshan Uranium Ore Field of Jiangxi Province

依据江西省相山矿田的深部钻探成果，结合近些年来矿田内零星发现的多金属矿化，确定相山深部埋藏有丰富的多金属矿产资源，成矿潜力深度超过2500m。将相山地区发现的多金属矿化分为两大类，一类为成矿深度相对较浅的铅锌矿，另一类为成矿深度较大的铜矿，认为相山地区的矿化是上铀中铅锌金下铜的成矿空间模式。研究发现铅锌矿主要与碳酸盐脉相伴生产出．铜矿化与硅化关系密切，利用电子探针和扫描电镜发现方铅矿内不均匀的分散有Ag元素，Au元素以均匀质点分散在方铅矿内，以晶格金的形式参与矿物晶格构架。通过分类研究矿化围岩、低品位矿石和高品位矿石各自的硫、铅同位素组成和计算硫同位素平衡温度．认为相山深部多金属成矿以中低温为主，同时局部存在明显的中高温成矿作用。判断成矿物质主要来自于周围的变质岩基底，同时混合部分地幔成矿物质，后期源于上地壳的多次热液改造作用对于Ph、Zn、Cu、Au等元素的富集成矿起到了决定性的作用。对比前人在德兴一遂川多金属矿集区的研究成果，发现相山地区多金属矿化在成矿物质来源上具有矿集区的普遍特征。但在成矿温度方面相山深部多金属成矿以低温为主（114℃-174℃），这与成矿带内以中温（200℃-340℃）为主的成矿作用有较明显的差异，推测它与相山地区勘探深度和不同类型矿化埋深的差异有关。

This work was based nn scientific deep drilling as well as combination with the recent discoveries of scattered polymetallic mineralization in the Xiangshan ore field of Jiangxi province.It was determined that rich metal resources were buried deeply beneath this area,with potential mineralization at the depth mm＇e than 2500 meters.Such polymetallic mineralization can be divided into two eategnries,the first is lead-zinc ore which is relatively shallow, and Ihe second is copper ore at larger depth.Our work suggests that a spatial model of mineralization with uranium in the upper, lead, zinc, gold in the middle,and copper in the lower can characterize this ore field. Research shows lead-zinc and copper ores are closely associated with calcite and silicifieation,respectively.Electron probe and SEM observation reveal Ag unevenly scattered in galena,and Au evenly distributed in galena and structure mineral crystal lattice. By calculating sulfur isotopic equilibrium temperature and classified study on the sulphur and lead isotope of wall rock, low-grade ore and high-grade ore, we came to the conclusion that the Xiangshan deep polymetallie mineralization is mainly of low temperature, partly of medium-high temperature.We infer tbat the metallogenic material was mainly from metamorphic basement, mixture with some mantle material.The late stage of upper crust hydrothermal refnrmation might have a crucial role in enrichment and mineralization of Pb,Zn,Cu,and Au.Cumpared with previous researches in the DexingSuichnau polymetallie mineralization concentration field,we think that the Xiangshan ore field has a common characteristic with ore-concentrated areas in souree of metallogenie material,but obviously different in metallogenic temperature, i.e.dominated by low temperature （ 114 -174℃ ）., rather than meso- thermal （200℃ - 340℃ ） as in other the metallugenic zones.We speculate that this difference is related with exploration depth and variahle types of mineralizalion at different depths in the Xiangshan ore fieht.