云南新山金矿床金矿物形貌成分特征及矿床成因意义

摘要

By use of the optical microscope and electronic probe as main tools,this paper focused on the morphology,chemical composition,occurrences of gold minerals in the primary gold ores in Xinshan gold deposit in Yunnan Province,and their ore genetic significances was discussed in association with geological and mineralizing conditions.The results show that the gold minerals belong to Au-Ag solid solution series in which minor mercury and bismuth incorporated.In this solid solution series,electrum is the dominant species, argentiferous native gold in the second proportion and native gold is minor species.Pyrite is the dominant gold carrier mineral,and the occurrence of gold minerals is observed included gold,fissure-filled gold and intergranular gold.As the hydrothermal gold mineralizing process developed,affected mainly by the gentle decrease of fluid temperature and acidity and weak and ajusting activity of ore-controlling fault,gold minerals crystallized orderly as native gold at first,then argentiferous native gold and electrum finally,and following this order,their occurrence changed orderly as included,fissure-filled and intergranular gold.The chemical composition, occurrences and their variation regularities suggest Xinshan gold deposit is mesothermal deposit and there is prospecting potentiality at the unexplored deeper part of the minig area.%以新山矿区原生金矿石为研究对象，采用光学显微镜及电子探针研究等手段，系统研究了金矿物的形貌、赋存方式与化学成分特征，并结合矿区地质矿化特征讨论其矿床成因指示意义。研究结果表明，区内金矿物为含铋、汞的金银系列矿物，主要为银金矿，其次为含银自然金，少量为自然金，黄铁矿为其主要载体矿物，金矿物以包裹金、裂隙金及粒间金形式产出。随热液成矿作用演化，受成矿流体温度、酸度缓慢降低及控矿断裂的调整式活动制约，金矿物由自然金向含银自然金再向银金矿有序变化，赋存形式也由包裹金向裂隙金再向粒间金有序变化。金矿化化学成分、赋存形式及其变化特征显示，矿床为中深成热液矿床，矿区深部仍有找矿远景。