摘要
金青顶金矿是胶东东部一个特大型石英脉型金矿床,其探测深度已达约1 340m,含矿石英脉的围岩主要为黑云二长花岗岩。文中对蚀变围岩中钾长石、斜长石和石英等主要矿物的结构与形态特征进行了详细观察及成因分析,发现热液成因钾长石大量存在于近矿围岩中,且深部钾长石化强度和范围都有加大的趋势,并大量出现由正长石和石英组成的团块状似伟晶岩。关于热液钾长石的形成温度,目前尚无可靠的测试数据。文中运用二长石温度计对蚀变岩中条纹长石平衡温度进行了估算,获得似伟晶岩中条纹长石平衡温度为433～482℃,而钾长石化叠加弱黄铁矿化花岗岩中条纹长石平衡温度为362～419℃。从似伟晶岩到钾长石化花岗岩、钾长石化叠加黄铁绢英岩化花岗岩中条纹长石平衡温度的渐次降低,反映了成矿流体与围岩反应逐渐弱化的特征。
The Jinqingding gold deposit located in the east of the Jiaodong Peninsula is currently the largest single quartz-vein type of gold deposit in China. Its detection depth has reached about 1340 m and the wallrock is mainly biotite adamellite. Field observations show that massive volumes of hydatogenic potash feldspars occur in the altered wallrocks close to orebodies and from shallow to deep, the range and intensity of potash feldspathization tend to be large and high. A large amount of lumpy pegmatoid rocks were found in the deep mainly composed of orthoclase and quartz. In this paper, configuration and structure of main minerals, like potassium feldspar, plagioclase and quartz were observed in detail and the equilibrium temperature of hydrothermal potash feldspars was estimated for the first time using two-feldspar geo-thermometer on the basis of the microprobe analysis. The analysis reveals that the temperatures of perthites in pegmatoid rocks range from 433 ℃ to 482 ℃, and in potash feldspathized granites range from 362 ℃ to 419 ℃, indicating that the interaction between metallogenic fluids and wallrocks gradually tends to weaken.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2013年第3期94-103,共10页
Earth Science Frontiers
基金
国家自然科学基金项目(90914002)
全国危机矿山接替资源找矿项目(20089937)
中国地质调查局工作项目(1212011220926)
国土资源部公益性行业科研专项经费项目(200811011)
关键词
钾长石化
二长石温度计
流体
金青顶金矿
胶东
potash feldspathization
two-feldspar geo-thermometer
fluid
Jinqingding gold deposit
Jiaodong
