胶东上庄与夏甸金矿床金红石化学成分标型特征研究

对上庄与夏甸金矿的含矿花岗岩、绢英岩以及黄铁绢英岩中的金红石化学成分标型特征进行了详细的研究,探讨了其中Fe、Si、Ti、W元素含量变化的规律。研究表明,上庄金矿与夏甸金矿中的金红石为变质成因,主要通过黑云母蚀变释放Ti而形成金红石,此类金红石主要赋存在黑云母的边缘、解理及裂隙之间。金红石中Ti含量存在由绢英岩向黄铁绢英岩的下降趋势。矿体周围能够形成Ti晕,可作为强烈矿化的标志。另外,金红石中W的含量从花岗岩到绢英岩再到黄铁绢英岩呈现不断富集的趋势,表明金红石中W的含量变化可指示金矿化的强弱,高W金红石的出现指示金矿的形成,这为胶东金矿的找矿研究提供了新的思路。

Typomorphic features of the rutiles from the Shangzhuang and Xiadian Au deposits in Jiaodong Peninsula

The Jiaodong (eastern Shandong) hydrothermal gold deposits consisting of several world-class gold deposits have been producing a great majority of gold in China. The main types of mineralization are characterized by the distribution of gold within quartz veins and altered rocks, with the latter being more important. There are still many controversies about the evolution of metallogenic indicators and tracer elements in Jiaodong gold deposits. As rutile has great stability in the petrogenesis and metamorphism, the authors investigated detailed typomorphic characteristics and the chemical composition of rutiles from the fresh granites, sericitolites and beresites in Shangzhuang and Xiadian gold deposits and made dating by electron microprobe analysis. The genetic type of rutile and its change of Fe-Si-Ti-W content were discussed. Detailed studies reveal that rutiles in Shangzhuang and Xiadian gold deposits are mainly of metamorphic origin and were mainly formed by the alteration of biotite with the release of Ti. Moreover, this kind of rutile is mainly distributed at the edge of biotite. Ti values of rutiles exhibit a decreasing trend from sericite to beresite, forming a Ti halo that can be used as a sign of gold enrichment. In addition, W content in rutile has another enrichment trend from fresh granite through sericitolite to beresit, indicating that W can be used as an indicator to trace gold migration. These signatures can be regarded as evaluation indices for delineating the gold target and can provide new models for the study of gold deposits.