Geological characteristics and ore-forming material sources of the Pangjiahe gold deposit in Shaanxi Province

Abstract：Ores in the Pangjiahe gold deposit are mainly distributed in upper Devonian Xiadonggou Formation rocks consisting of chloritized sericite phyllite and blastopsammitic quartz sandstone，which constitute a gold-bearing rock series and abundant source layers of gold. Gold ore bodies are mostly preserved in interlayer compresso-crushed zones which assume expansion, contraction, branching, compounding and wavelike bending. Ore bodies exhibit layered and lenticular shapes. Minerals mainly include native gold and electrum. Gold-bearing minerals are pyrite and arsenopyrite. The relevant gold mineralization alterations include pyritization and arsenopyritization. The metallogenic epoch can be mainly divided into three stages, namely quartz-coarse pyrite-hydromica stage, fine pyrite-arsenopyrite stage and pyrite-quartz-carbonate stage. The analyses of δ34S, δ18O and stable lead isotope show that Pb of gold ore bodies was derived mainly from the upper crust and partly from the mantle. δ34S and δ18O also show that gold ore-forming fluid was derived mostly from the crust and partly from magma in the mantle. In a word, gold ore-forming materials were derived from mixed sources.