Abstract:

Taiyangsi gold polymetal deposit in Liangdang Country, western Qinling is a supper large gold deposit. Danfeng Group is a principle ore-bearing rock formation with gold, silver and lead-zinc mineralization. The volcanic rocks of Danfeng Group mainly consist of basalts and a few of andesite and rhyolite. The meta-basalt of Danfeng Group is characterized by high content in Al₂O₃ and low content in TiO₂. The trace elements in the meta-basalt show the same characteristics as the island-arc tholeiite. The REE distribution patterns with high value of ∑REE，enrichment of LREE and incline to the right are similar to the island-arc tholeiit. The rock association, lithochemical and geochemical characteristics of Danfeng Group show its immature island-arc environment at Early Paleozoic. The large volcanic activities formed the primitive earth crust and the initial ore-source bed around the Taiyangsi area. The remobilization of ore-bearing hydrothermal solution formed further mineralization and enrichment in gold, silver, lead and zinc through the fractures and modification.

Key words: geotectonic setting, lithology, geochemistry, island-arc environment, metallogenic, Danfeng Group, western Qinling