Sulfide S and Pb Isotopic Constraint on the Genesis of Diyanqinamu Mo-Pb-Zn Polymetallic Deposit, Inner Mongolia, China |
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The Great Hinggan Range (GHR) hosts many large Mo deposits and vein-type Pb-Zn deposits and is one of the most important polymetallic metallogenic belts in China. Although Mo and Pb-Zn deposits are locally closely related in space in the GHR, it is disputed whether the Mo and Pb-Zn deposits have a genetic relationship. The Diyanqinamu Mo deposit located at the middle part of the northern GHR is a Late Jurassic large porphyry Mo deposit and closely adjacent by vein-type Pb-Zn deposit. In this work, we discussed the relationship between Mo and Pb-Zn deposits in Diyanqinamu mine based on the data of S and Pb isotopic geochemistry and geological information. In this mine, the Mo deposit is concentrated in the southern area with a distance of 500 m to the vein Pb-Zn deposit. The delta S-34(CDT) values of the galena and sphalerite from the Mo deposit range from +1.73 parts per thousand to +7.29 parts per thousand with average of +5.04 parts per thousand. By contrast, delta S-34(CDT) values of the galena and sphalerite from the Pb-Zn deposit, ranging from +2.38 parts per thousand to +5.46 parts per thousand with average of +4.04 parts per thousand, is similar to that of the Mo deposit. The formation temperatures of the Pb-Zn deposit calculated based on the sulfur isotope balance fractionation between sphalerite and co-existed galena range from 220 degrees C to 315 degrees C (average 247 degrees C), which is lower than that of the Mo mineralization (292-510 degrees C). Pb isotopic results show that the Pb-206/Pb-204, Pb-207/Pb-204, and Pb-208/Pb-204 values of the Pb-Zn deposit range from 18.326-18.364, 15.541-15.589, and 38.054-38.214, respectively, which are slightly higher than those of the Mo deposit ranging from 18.287-18.331, 15.532-15.569, and 38.034-38.139, respectively. In the Pb-206/Pb-204?Pb-207/Pb-204 diagram, sulfides sampled from the Mo and Pb-Zn deposits overlapped with each other and formed a linear distribution, indicating that they are derived from a mixed metal source with more external contribution to the Pb-Zn mineralization. This mixed signal is further confirmed by the geologic facts that the host rocks of the vein-type Pb-Zn deposit have abnormally high contents of Pb, Zn, and Ag, and experienced strong hydrothermal alteration. Combined with the ore geology, mineral assemblage, and isotopic geochemistry of the two types of mineralization, we propose that the Mo and Pb-Zn deposits in the Diyanqinamu mine represent different faces of the same porphyry system. This Mo-Pb-Zn metallogenic system would provide important clues on further prospecting of Mo and Pb-Zn resources in the GHR.
Publication name |
MINERALS Volume: 10 Issue: 4 Article Number: 304 DOI: 10.3390/min10040304 Published: APR 2020 |
Author(s) |
Sun, Hairui; Huang, Zhilong; Lu, Zhicheng; Yu, Xiaofei; Li, Yongsheng |
Corresponding author(s) |
SUN Hairui hairuisun@126.com China Geol Survey, Res Dev Ctr, Beijing 100037, Peoples R China. Chinese Acad Sci, Stake Key Lab Ore Deposit Geochem, Inst Geochem, Guiyang 550081, Peoples R China. | View here for the details
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