豫西吉家洼金矿成矿作用过程:来自成矿流体的约束  

Metallogenic Process of the Jijiawa Gold Deposit in Western Henan:Constraints from Fluid Inclusions

作　　者：张兴康[1] 叶会寿[2] 李正远[1] 颜正信[3] 王小雨[1] 韩新志[3] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室,北京100037 [3]河南省地质矿产勘查开发局第一地质矿产调查院,河南洛阳471023

出　　处：《现代地质》2014年第4期686-700,共15页Geoscience

基　　金：国土资源部成矿作用与资源评价重点实验室开放研究项目(ZS1314);中国地质调查局地质调查项目(12120114035401;1212011220869)

摘　　要：豫西吉家洼金矿位于熊耳山金多金属矿集区西部，是一构造蚀变岩-石英脉混合型金矿床。其热液成矿过程包括4个矿化阶段：黄铁矿-石英阶段（Ⅰ）、石英-黄铁矿阶段（Ⅱ）、石英-多金属硫化物阶段（Ⅲ）和石英-碳酸盐阶段（Ⅳ）。通过流体包裹体显微测温、拉曼光谱和H、O同位素分析，获得了成矿流体的温度、盐度、密度和成矿流体的类型和来源，探讨了成矿作用的机理。其结果显示如下：Ⅰ、Ⅱ阶段发育CO2三相包裹体和气液两相包裹体，Ⅲ、Ⅳ阶段主要发育气液两相包裹体。从第Ⅰ阶段到Ⅳ阶段，流体包裹体的均一温度分别为232～333℃、143～266℃、135～227℃和106～166℃；对应的盐度为3.76％～16.05％、1.74％～17.34％、0.7％～17.26％和0.35％～11.34％。表明成矿流体由早阶段中低温、中低盐度的CO2-H2 O-NaCl体系，向晚期的低温、低盐度的H2 O-NaCl体系演化。H、O同位素组成特征显示，成矿流体以岩浆水为主，有不同比例大气降水混合。流体混合作用和流体不混溶作用是促使金发生沉淀、富集的重要因素，水-岩反应对金的沉淀也有促进作用。The Jijiawa gold deposit is located in the western part of Xiong＇er mountain gold polymetallic ore dis-trict,Henan Province.It represents a mixing gold deposit,consisting of structure-controlled alteration type,as well as the quartz vein type.The ore-forming process can be divided into four stages：pyrite-quartz vein stage （Ⅰ）,quartz-pyrite vein stage（Ⅱ）,quartz-polymetallic sulfides stage（Ⅲ）,quartz-carbonate vein stage（Ⅳ）. Through the studies of fluid inclusion microscopic temperature measurement,Laser-Raman spectra and H and O isotopes,we obtained the ore-forming fluid temperature,salinity,density and the type and source of ore-forming fluid,and discussed the mechanism of mineralization.The results show as follows：Two types of fluid inclusions in stage Ⅰ and Ⅱ are indentified as CO2 type and gas-liquid type;but stage Ⅲ and Ⅳ quartz contain exclu-sively gas-liquid type fluid inclusions.The homogenization temperatures of ore-forming fluids from stage Ⅰ to stage Ⅳare 232-333 ℃,143-266 ℃,135 -227 ℃and 106-166 ℃respectively,with the corresponding salinities being 3.76%-16.05%,1.74%-17.34%,0.7%-17.26% and 0.35%-1 1.34%.In general, the ore-forming fluid was evolved from CO2-H2 O-NaCl system,which is characterized by medium-low tempera-ture and medium-low salinity,to H2 O-NaCl system.The H-O isotopes composition reveals that in the Jijiawa gold deposit,the hydrothermal system gradually transited from a magmatic-dominated fluid to a meteoric-domi-nated fluid.Fluid mixing action and fluid immiscibility are the most important factors that caused the gold pre-cipitation and enrichment,and fluid-rock interaction also contributes to the gold precipitation and enrichment.

关 键 词：流体包裹体 H O同位素 成矿流体 流体不混溶 吉家洼金矿 熊耳山 

分 类 号：P618.51[天文地球—矿床学] P611.1[天文地球—地质学]