摘要
青海东昆仑是中国又一个重要的、极富潜力的金属成矿带。文章对区域地质构造环境与演化及典型金矿床地质特征进行了研究 ,并对区域金成矿作用进行了初步分析。结果表明 ,东昆仑是一个具有复杂演化历史的多旋回复合造山带 ,其中产出的金矿床不仅具有相似的基本地质特征 ,而且与早古生代和晚古生代—早中生代复合造山过程有密切的成因联系 ,并在产出构造环境、矿体特征、控矿构造、围岩蚀变、矿物组成和元素组合等方面与一般造山型金矿床极为相似 ,因此 ,应属典型的造山型金矿床。硫、铅同位素显示成矿物质为少量地幔与围岩地层混合的产物 ,金矿床主成矿时代对应于区域晚华力西 印支造山作用的晚期 ,流体不混溶是该区流体演化和成矿流体形成的重要机制。
The East Kunlun area in Qinghai Province is a very important and promising metallogenic belt,where several gold deposits were recently found in different tectonic units. Regional geological setting and evolution,basic geological characteristics of the major gold deposits and regional gold mineralization are discussed in this paper. The East Kunlun area is a multiple orogenic belt which underwent very complicated evolutionary processes. Having many similar geological characteristics,the gold deposits here are related genetically to early Paleozoic and late Paleozoic-early Mesozoic orogenic processes. In addition, they are also similar to orogenic gold deposits in other regions in such aspects as tectonic setting,orebody distribution,ore-controlling structures,wall rock alteration and mi-neral composition. Therefore,they should belong to a type of orogenic gold deposits according to the classification proposed by Groves et al.(1998). Sulfur and lead isotopes suggest that the ore-forming materials are mainly derived from wall rocks and partly from the mantle. Ar-Ar dating shows that gold mineralization mainly occurred in Indosinian. According to detailed studies of fluid inclusions,it can be concluded that the immiscibility of a homogeneous CO 2-H 2O parent fluid is a very important mechanism responsible for fluid evolution and the formation of ore-forming fluid.
出处
《地球学报》
EI
CAS
CSCD
北大核心
2004年第4期415-422,共8页
Acta Geoscientica Sinica
基金
国土资源部"九五"科技攻关项目 ( 95 0 2 0 0 5 )
国家地质调查项目 (K1.1.3 .1
DKD2 0 0 10 2 7 4)资助
关键词
复合造山
金矿
地质特征
青海
orogenic gold deposit multiple orogenic processes geological characteristics East Kunlun