西秦岭与埃达克岩和喜马拉雅型花岗岩有关的金铜成矿及找矿问题  

Issues on metallogenesis and prospecting of gold and copper deposits related to adakite and Himalayan type granite in west Qinling.

作　　者：张旗[1] 殷先明 殷勇[3] 金惟俊[1] 王元龙[1] 赵彦庆[4] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]甘肃省地矿局,兰州730000 [3]甘肃地矿科技信息中心,兰州73000 [4]甘肃省地质调查院,兰州73000

出　　处：《岩石学报》2009年第12期3103-3122,共20页Acta Petrologica Sinica

基　　金：国家自然科学基金重大研究计划(90714011)资助

摘　　要：秦岭金矿分布广,目前学术界大多认为分属于造山型和卡林型金矿两类。该区印支期花岗岩发育,大多具有埃达克岩和喜马拉雅型花岗岩(低Sr和Yb)的特点,与金铜矿在时空分布上相关。美国内华达州卡林型金矿是世界级的金矿聚集区,与卡林型金矿有关的第三纪岩浆岩(中酸性火山岩和浅成花岗岩)也具有埃达克岩和喜马拉雅型花岗岩的地球化学特征,暗示内华达卡林型金矿也来源于加厚下地壳的底部。本文讨论了埃达克岩和喜马拉雅型花岗岩有利于成矿的机理,并根据西秦岭金矿与花岗岩分布的关系,提出以夏河-宕昌-两当-凤县为界将西秦岭划分为南北两个成矿区和13个成矿聚集区:北区花岗岩发育,有利于寻找斑岩型、夕卡岩型等热液型金铜矿床;南带侵入岩少而小,有利于寻找远离岩体的金矿(包括卡林型等)。鉴于西秦岭印支期埃达克岩和喜马拉雅型花岗岩发育,金铜尤其是金矿分布多,储量大,且大多与埃达克岩或喜马拉雅型花岗岩有关,可能是中国金矿最具潜力的地区,有利于特大型金铜矿的产出,可能发展成为中国最大的金矿聚集区。为此,建议加强本区花岗岩与金铜成矿关系的研究,革新找矿思路和找矿技术方法,以实现找矿的新突破。Gold deposits spreading extensively in west Qinling have been grouped into such two types as orogenic type and Carlin type, which is accepted by most researchers of the present academic field. In the study area developed Indo-chinese epoch granite, most of which have the characteristics of adakite and Himalayan type granite ( relatively low content of Sr and Yb), and related to distribution of gold and copper deposits spatially and timely. The study on Carlin type gold deposits in Nevada, USA show that it is a world-level concentration area of gold deposit, Tertiary igneous rock ( intermediate-acid rock and hypabyssal granite) related to gold and copper deposits have the geochemical characteristics of adakite and Himalayan type granite which indicate that the sources of Carlin type gold deposit in Nevada come from the bottom of thickened lower crust. In the paper the metallogenetic mechanism of adakite and Himalayan type granite was discussed, west Qinling was divided into two metallogenetic regions as north and south with the boundary of Xiahe-Tanchang-Liangdang-Fengxian, including 13 metallogenetic concentration areas. In the north region, the developed granite is favorable to search porphyry type, skarn type and hydrothermal type gold and copper deposit; in the south region, it is good to search gold deposits away from igneous rock mass (including Carlin type, sedimentary type, rupture zone type and altered rock type, etc.). West Qinling where Indo-chinese adakite and Himalayan type granite developed extensively, most gold and copper deposits with the features of wide distribution and high reserves are related to adakite and Himalayan type granite should be developed the most potential gold region.

关 键 词：西秦岭 埃达克岩 喜马拉雅 印支期花岗岩 金铜成矿关系 找矿思路 问题 Carlin type GOLD deposit related copper DEPOSITS 卡林型金矿 GOLD DEPOSITS geochemical characteristics IGNEOUS rock 聚集区 金铜矿床 region 秦岭金矿 时空分布 中酸性火山岩 

分 类 号：P58[天文地球—岩石学]