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The Jinchanghe Pb-Zn polymetallic deposit is a representative distal skarn deposit in the Baoshan block. Due to limited research on the sources of ore-forming metals and trace elemental geochemistry of sulfides, the sources and mineralization environments of the Jinchanghe skarn Pb-Zn polymetallic deposit are still controversial. In this study, copper and sulfur isotopes and trace elements of sulfides from the Jinchanghe Pb-Zn polymetallic deposit were analyzed to reveal the sources of ore-forming materials and the ore-forming environments. The trace elemental analysis results show abundant Co, Ni, Mn and Se elements, and less As, Tl and Sb elements dominantly enter pyrite by isomorphic substitution, except for some Zn and Cu that occur as sulfide inclusions in Py1. Abundant Fe and Mn elements could substitute Zn to enter the sphalerite crystal lattice by the isomorphic substitution mechanism of (Fe2+ + Mn2+) ↔ 2Zn2+, and less Ag and Sb elements could enter the sphalerite by the isomorphic substitution mechanism of (Ag+ + Sb3+) ↔ 2Zn2+. The Cu-S isotopic and trace elemental compositions jointly suggest that the Jinchanghe distal skarn Pb-Zn polymetallic deposit formed from magmatic hydrothermal fluids with a sedimentary host-rock contribution, under mesothermal conditions (260 °C on sphalerite). [ABSTRACT FROM AUTHOR]

The Beiya giant porphyry Au deposit is the largest Cenozoic Au deposit in the Jinshajiang Cu–Mo–Au metallogenic belt. Many granite porphyries of ~36 Ma were exposed in the Beiya deposit, including the Wandongshan (WDS) and Hongnitang monzogranite porphyries (HNT–MPs) with economically important Au metal resources, the uneconomic WDS biotite MP, and Putaishan granite porphyry (GP), and subeconomic MPs at Nandaping (NDP) and Matouwan (MTW) prospects. To reveal the fundamental factors that lead to the different fertility of these granitic porphyries, this study uses the biotite and zircon geochemical compositions to evaluate their petrogenetic and magmatic conditions (e.g., F content, pressure, fO2). The results show that biotites from economic WDS and HNT–MPs exhibit moderate F contents (0.85%–2.16%), low n(FeT)/n(FeT + Mg) ratios (average of 0.36), and shallow emplacement depths of 0.19–1.76 km. In contrast, the uneconomic granite porphyries are characterized by variable F contents (0.17%–2.75%), high n(FeT)/n(FeT + Mg) ratios (average of 0.43), and deep emplacement depths of 2.76 to 5.02 km. Moreover, the economic WDS and HNT–MPs display higher average zircon fO2 (ΔFMQ [fayalite–magnetite–quartz] of +0.88) than uneconomic granite porphyries (ΔFMQ of −0.19), further confirming a higher fO2 of the economic granitic porphyries. These features indicate that magmatic fO2 is a critical factor controlling Cu–Au mineralization at the Beiya Au deposit. In comparison with the economic WDS and HNT–MPs, the subeconomic MPs in the MTW and NDP prospects exhibit higher average biotite n(FeT)/n(FeT + Mg) ratios of 0.47 and 0.45, and lower average zircon ΔFMQ of −0.05 and −0.23, suggesting lower magmatic fO2 and thus have relatively weak potentials to form Cu–Au mineralization. Notably, the economic WDS and HNT–MPs have higher biotite XMg ratios than those of the subeconomic and uneconomic granitic porphyries, indicating that the economic MPs were formed by the partial melting of mixed lower crustal materials with more mantle‐derived materials. Therefore, the addition of mantle‐derived materials played an important role in determining the fO2 of the granitic porphyry, thus primarily controlling its fertility of Cu–Au mineralization. [ABSTRACT FROM AUTHOR]

Focuses on a study on the sulfur isotope geochemistry of the Lemachang independent silver deposit in northeastern Yunnan Province, China and the mechanism of sulfur isotope equilibrium between barite and freibergite below three-hundred degrees celsius. Geology of the Lemachang deposit; Sulfur isotopic analysis; Discussion and conclusions.

Focuses on a study of an oxygen isotope as a tracer of rare earth element fractionation in water-rock interaction in the Lemachang independent silver deposit in Yunnan, China. Geology of the Lemachang deposit; Samples and analysis; Discussion and conclusions.