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Genetic link between gold mineralization and porphyry magmatism in the Baogutu district, West Junggar, NW China: Constraints from Re‐Os and S isotopes in sulphide
Author(s) -
An Fang,
Zhu Yongfeng,
Richards Jeremy P.,
Creaser Robert A.,
Chen Lin,
Zheng Bo,
Lehmann Bernd
Publication year - 2020
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3795
Subject(s) - isochron , magmatism , geology , diorite , geochemistry , mineralization (soil science) , pyrite , igneous rock , genetic model , crust , mantle (geology) , tectonics , zircon , paleontology , chemistry , biochemistry , soil water , gene , soil science
Baogutu is a large gold deposit (4 Mt @ 5.5 g/t Au) in West Junggar, NW China. We conducted a Re‐Os geochronological study on seven pyrite samples from auriferous quartz‐pyrite veins, which yielded a Re‐Os isochron age of 312 ± 11 Ma (2σ). This age defines the timing of gold mineralization, and overlaps the emplacement age of diorite to granodiorite porphyry stocks (319–310 Ma) in the Baogutu district. The Os initial ratio of 0.46 ± 0.21 (2σ) suggests a mix of components from both mantle and continental crust in the ore‐forming system, which is similar to the proposed magma source of porphyry stocks. The δ 34 S values of sulphide minerals vary in a narrow range from +0.1 to −3.3‰, indicating that the sulphur is likely of igneous origin. Our data suggest that the Baogutu gold mineralization is probably genetically linked to the regional diorite to granodiorite magmatism. The new data provide important constraints for an evolving genetic model of the Baogutu gold deposit.