川西铜炉房造山型金矿床成因:基于矿物学、流体包裹体和热力学模拟的证据  

Ore genesis of the Tonglufang orogenic gold deposit in western Sichuan:Constraints from mineralogy,fluid inclusions,and thermodynamic simulations

作　　者：周春波 葛行飞 屈尚伦 沈开红 徐勇 刘洋 黄皓南 角兴宇 裴秋明 梁翼 ZHOU Chunbo;GE Hangfei;QU Shanglun;SHEN Kaihong;XU Yong;LIU Yang;HUANG Haonan;JIAO Xingyu;PEI Qiuming;LIANG Yi(Sichuan Geophysical Survey and Research Institute,Chengdu 610032,China;Department of Geological Engineering,Faculty of Geosciences and Environmental Engineering,Southwest JiaotongUniversity,Chengdu 611756,China;Kangding Municipal Bureau of Natural Resources,Kangding 626000,China)

机构地区：[1]四川省地球物理调查研究所,成都610032 [2]西南交通大学地球科学与环境工程学院,成都611756 [3]康定市自然资源局,四川康定626000

出　　处：《成都理工大学学报(自然科学版)》2025年第2期253-269,I0004,I0005,共19页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家自然科学基金项目(41702077);中央高校基本科研业务费专项资金(2682016CX090)。

摘　　要：四川省铜炉房金矿床位于松潘—甘孜造山带东南部的“姑咱—孔玉—丹巴”金成矿区,矿石类型主要包括富黄铁矿石英脉、含硫化物石英脉以及孔雀石−褐铁矿石英脉。根据野外调查与镜下观察,其金成矿作用可划分为2个阶段:石英−金−黄铁矿阶段和石英−金−多金属硫化物阶段。通过电子探针、流体包裹体测温、LA-ICP-MS元素扫面、热力学模拟等方法研究铜炉房金矿床的成因类型。电子探针结果显示金成色值范围较大,为568~915.1。流体包裹体显微测温显示其均一温度的峰值为300~320℃和360~380℃,盐度(NaCl_(eqv))的峰值为8%~10%和12%~14%,指示成矿流体属于中低温、中盐度的H_(2)O-NaCl-CO_(2)体系。LA-ICP-MS元素扫面显示,Ⅱ阶段黄铁矿要比Ⅰ阶段更富集As,Au,Ag,Cu,Pb,Zn,Co,Ni,Bi,Sb元素,但两阶段黄铁矿的Au/Ag均较低。矿物组合和成矿流体特征表明铜炉房金矿床属于造山型成因,金成色值及黄铁矿微量元素特征暗示起源于幔源流体。The Tonglufang gold deposit is located in the southwestern part of the Songpan-Ganzi orogenic belt,in the Guza-Kongyu-Danba gold metallogenic province.Gold-bearing ores in the Tonglufang deposit are mainly found in pyrite-rich quartz veins,sulfide-rich quartz veins,and malachite/limonite-rich quartz veins.Based on a field investigation and microscope analysis,the gold mineralization is divided into two stages:(Ⅰ)a quartz-gold-pyrite stage and(Ⅱ)a quartz-gold-polymetallic sulfide stage.In this paper,the genetic types and mineralization characteristics of the Tonglufang gold deposit are analyzed by means of electron probe microanalysis(EPMA),fluid inclusion,laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)mapping,and thermodynamic calculations.The microthermometric analysis of fluid inclusions reveals two homogenization temperature peaks(300~320℃ and 360~380℃)and two salinity(NaCl_(eqv))peaks(8%~10% and 12%~14%),indicating low to intermediate temperature and salinity in the ore-forming,H_(2)O-NaCl-CO_(2)-type fluid.The LA-ICP-MS mapping analysis shows that the contents of trace elements including As,Au,Ag,Cu,Pb,Zn,Co,Ni,Bi,and Sb are much higher in the pyrite at stage Ⅰ than those at stage Ⅱ,while the Au/Ag ratios are low in the pyrite in both stages.The characteristics of the ore-forming fluids and mineral assemblages may indicate the Tonglufang deposit is an orogenic gold deposit,while the range of gold fineness and trace element composition of pyrite may indicate a mantle-fluid origin.

关 键 词：金成色值 流体包裹体 LA-ICP-MS 铜炉房金矿床 松潘—甘孜造山带 

分 类 号：P611[天文地球—矿床学]