Characteristics of explosion breccia type gold deposit in Hulalin, Inner Mongolia

The main strata of the Hulalin gold deposit are composed of terrigenous clastic rocks of Middle Jurassic period, and the magmatites in the gold deposit area are dominated by the granite-porphyries and quartz-porphyries of Yanshan Period. The explosion breccias develop near the contact zone between strata and rock bodies. The gold bodies mainly develop in the explosion breccia pipes controlled by the fault structures. There are 6 gold bodies blocked out in the ore district, the general trend is about SN, and the No.1 and No.2 of them are the dominant ore bodies. The mineralization relative to the explosion breccias and forms a distribution of one-body with multi-shapes. δ~(34)S ranges from -0.2‰～0.8‰ and shows S features of plutonic magmas. The studies of S and Pb isotopes, fluid inclusions and rare-earth elements indicate that the ore-forming materials derive from deep crust or mantle, and the ore-forming fluids derive from the deep magmatic hydrothermal solution. The ( )~(39)Ar/~(40)Ar dating of the ore-forming age was 135.5 Ma.