山东胶东地区某些金矿床的氩、氢、氧稳定同位素地球化学及矿床成因

    THE STABLE ISOTOPE GEOCHEMISTRY OF ARGON,HYDROGEN,OXYGEN AND ORE GENESIS OF SOME GOLD DEPOSITS IN THE JIAODONG REGION,SHANDONG PROVINCE

    • 摘要: 通过矿床地质特征、流体包裹体及氧、氢稳定同位素的研究,认为马家窑金矿属再平衡岩浆热液矿床,金青顶和十里铺金矿属大气降水热液矿床。马家窑金矿石英的δD、δ18O值高,变化小,比较稳定;蚀变岩石的δ18O在磺向上由围岩向矿脉逐渐升高。金青顶和十里铺金矿石英的δD、δ18O值低、变化大;蚀变岩石的δ18O值由地表向深部逐渐降低。开展金矿的氮稳定同泣素研究,在国内尚数首次。马家窑金矿36Ar在温度300℃以下相对含量不到10%,金青顶和十里铺金矿36Ar则达90%以上,表明前者以岩浆成因40Ar为代表,后者则以大气氩36Ar为代表,进而表明马家窑金矿是再平衡岩浆热液成因,金青顶和十里辅金矿是大气降水热液成因。示踪结果与H、O同位素一致,表明氩同位素在示踪成矿热液、矿床成因研究方面是一种较为有效的手段。

       

      Abstract: Based on the study of the geological characteristics, fluid inclusions and stable isotope compositions of hydrogen, oxygen and argon of the gold deposits in the Jiaodong region, it is suggested that the Majiayao gold deposit belongs to the hydrothermal one, formed from re-equilibrated magmatic water whereas the Jinqingding and shilipu gold deposits——hydrothermal deposits dominated by meteoric water.The δD and δ18O values of quartz in the Majiayao gold deposit are relatively high and stable with only a small variation;the δ18O values of the altered rocks increase gradually from wall rocks to ore veins. The δD and δ18O values of quartz in the Jinqingding and shilipu gold depesits are relatively lower with big variation;the δ18O values of altered rock decrease gradually from the surface down to the deep.

       

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