陕西勉略宁地块车渡磁铁石英岩型 金矿床多期成矿作用.

Based on the Held investigation and mineragraphy , the mineralization stages were identfied for Chedu gold depostt in Mianluening block of Shaanxi. According to the metamorphic degree of rock (ore) and crosscutting relationship of minerals , the mineralization can be divided into three stages：① sedimentary-metamorphic stage , high-grade layered gold ore body formed is accompanied by the sedimentation-metamorphism of magnetite quartzite；② hydrothermal mineralization stage , is divided into two substages , including smoky gray quartz sulfide vein and sulphide-bearing carbonate vein , in which native golds are observed；③ supergenesis stage , gold is further enriched to form large native gold grains accompanied by oxidization of magnetite. The native gold in Chedu gold deposit occurs as magnetite fractures, along the grain boundaries of magnetite and quartz, and within magnetite, pyrite, and calcite. The main occurrence states of gold inChedu gold deposit are intergranular gold, inclusion gold and tissure gold. Based on high- grade gold and distribution scale in quartz sulfide veins and sedimentary bands of magnetite quartzite, the genesis of Chedu gold deposit s classified as magnetite quartzite type, which s of great significance for the next geological prospecting in the area. [ABSTRACT FROM AUTHOR]