Abstract:

The Bojitian gold deposit is located in the east of Huijiabao anticline and is an important component of Huijiabao ore field. Gold mineralization occurred under low temperature and was closely associated with decarbonation, silicification, sulfidation and dolomitization. The deposit has a characteristic elemental assemblage of AuAsHg. Calcite mineralization with MREE enrichment and positive Eu anomalies characteristic show that the oreforming hydrothermal fluid might be a reductive fluid with a MREE relative enrichment and positive Eu anomalies. The oreforming fluid mainly originated from a plutonic source, and at least had undergone the fluidrock interaction for a plagioclaserich area. The δ13C value of -6‰-01‰ for the calcite vein formed in the oreforming stage and the δ13C value of 0.2‰3.2‰ for the calcite vein formed post the oreforming stage indicate that the carbon in the oreforming stage was from the mantle and the formation, and that the carbon post the oreforming stage was from the formation. The δ34S value of realgar varying from 073‰ to 586‰ with the characteristics of mantlederived sulfur indicates that the isotopic composition of sulfur of sulfides in the deposit is highly homogeneous. In general, we suggest that the orebearing materials and fluids of the gold deposit mainly originated from a plutonic source. In the Yanshan period, the oreforming fluids upwelled along the deep fault; when they were transported to the anticline core, the oreforming conditions were greatly changed, which led to the rapid enrichment and precipitation of gold and the formation of the Bojitian gold deposit.

Key words: REE, isotope, Carlintype gold deposit, Guizhou