与侵入岩有关金矿床的研究现状、存在问题及在中国的前景  

Intrusion-related gold deposits: current understanding, outstanding problems, and perspectives in China

作　　者：胡朋[1] 聂凤军[1] 江思宏[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质论评》2006年第4期539-549,共11页Geological Review

基　　金：国家"973"项目(编号2002CB412606);国家自然科学基金资助项目(编号40573025)的成果。

摘　　要：与侵入岩有关的金矿床是近年来识别出来的一种新的金矿类型。这类金矿床常在远离汇聚板块边缘的克拉通边缘环境中产出,与已知的W/Sn岩浆省叠加。它们具特征性的Au+Bi+W+Te+Sb+As等亲石元素金属组合,在时空上和成因上与中等还原的分异I型侵入岩密切相关,随就位深度的不同而显示不同的矿化特征。形成于地壳浅部环境(<5km)中的金矿床常与岩株、岩墙或岩床有关,金矿化大多数以浅成低温脉、网状脉或角砾岩筒产出;形成于地壳深部环境(>5km)中的金矿床常与深成侵入岩体有关,金矿化以席状脉、云英岩或浸染状块体产出。流体包裹体研究表明成矿流体的类型随着成矿深度的不同而显示有规律的变化,形成于较浅部环境中的金矿床一般包括高温(>350℃)、不混溶的盐水(>30%NaCleq)和低盐度(<5%NaCleq)含CO2液相包裹体;而形成于较深部环境中的金矿床含有大量低盐度含CO2液相(<10%NaCleq)包裹体,有些矿床晚阶段流体含有中高盐度(10%～40%NaCleq)的盐水。含CO2流体无论在挥发份的出溶过程中还是在金属迁移过程中都起了重要的作用。与侵入岩有关的金矿床在中国有广阔的找矿前景,而中国东部金矿省和钨/锡成矿省的叠加部位是寻找该类型矿床的有利地段。A new intrusion-related gold deposit type has been recognized recently throughout the world. The deposits usually situated in magmatic provinces near craton margins that are distal to active convergent plate margins, overlapping with known W/Sn provinces. The intrusion-related gold deposits have many consistent characteristics such as a diagnostic metal assemblages that combines Au with anomalous Bi, W, As, Te and Sb and typically low concentrations of base metals, and a spatial, temporal and genetic association with moderately reduced differentiated I-type intrusions. The deposits exhibit a range of characteristics that vary over a wide range of emplacement depths. Deposits in shallow crustal settings （〈5km） are associated with stocks, dikes and sills and include systems with epithermal-style veins to stockwork and breccia. Deposits in deeper settings （〉5km） are hosted by plutons containing sheeted veins, greissen and disseminated gold. Fluid characteristics also vary with depth. Deposits in shallow environments contain high-temperature （〉350℃）, immiscible brine （〉 30%NaCleq） and low-salinity （（5 %NaCleq） vapor that commonly contains carbon dioxide. Deposits in deeper environments contain abundant low-salinity, carbon dioxide-rich aqueous fluids （〈10 %NaCleq） that, in some deposits, are postdated by moderate- to high-salinity brines （10% ～ 40%NaCleq）. Carbon dioxide plays an important role not only during exsolution of volatiles from felsic magmas but during the transportation of gold. The perspectives of intrusion-related gold deposits in China is tremendous, especially in favorable districts where gold provinces overlapped with W/Sn provinces in eastern China.

关 键 词：与侵入岩有关金矿床 构造背景 岩浆背景 地质特征 流体 造山型 

分 类 号：P618.51[天文地球—矿床学]