Geochemical Characteristics and Geological Significance of the Tawangshan gold deposit in Dongfang City, Hainan Province

Abstract

The Tawangshan gold deposit is located in the southwest of the Gezhen ductile shear zone in southwestern Hainan Island. Major, trace and rare earth element characteristics of the least altered granites and altered granite ores, as well as the oxygen and hydrogen isotopic features of the quartz, the sulfur and lead isotopic features of the pyrites, galena from this deposit were systematically studied. The altered granite ores content of Fe2O3/(Fe2O3+FeO) ranges from 0.409 to 0.410, showing strong magma reducibility. REE characteristics of the granite ores are similar to those of the least altered granites, indicating a close relationship between the mineralization and granite. Hydrogen and oxygen analysis results show that the content of 18OSMOW ranges from 7.7‰ to 16.3‰, δ18OH2O ranges from 1.0‰ to 6.8‰, suggesting that the ore-forming fluid was the dual nature of the metamorphic and magmatic hydrothermal. The compositions of sulfur isotope and lead isotope imply that the metallogenic materials of the deposit derived from the deep magma mixing with the shell source material contamination. Ore deposit geological features reflect the obvious characteristics of magmatic hydrothermal and porphyritic granite is mineralized rocks, implying the deposit was formed in the post-collisional extensional tectonic setting