1. Petroleum evolution and its genetic relationship with the associated Jinding Pb[sbnd]Zn deposit in Lanping Basin, Southwest China.
- Author
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Ge, Xiang, Xiang, Jiajia, Jin, Yulin, Cen, Wenpan, Zhu, Guangyou, and Shen, Chuanbo
- Subjects
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HEAVY oil , *BITUMEN analysis , *SULFUR isotopes , *SULFATE pulping process , *ORE deposits , *SULFIDE ores - Abstract
The spatial association of hydrocarbons with metalliferous ore deposits is found worldwide and is particularly common to MVT Pb Zn deposits. Heavy oil and bitumen are found in the Jinding Pb Zn deposit within the Lanping Basin, South China. However, the temporal and genetic associations between hydrocarbons and the deposit are still controversial. To this end, integrating Raman analysis, Re Os geochronology and transmission electron microscopy analysis of the bitumen and in situ S isotope analyses of the sulfide, the petroleum evolution of the Jinding reservoir and its genetic relationship with the Pb Zn deposits were discussed. Bitumen Re Os data from this study and published works indicate that the late Triassic shales underwent two distinct oil-generation events before mineralisation (∼25 Ma), with initial oil generation occurring during the early Cretaceous (∼116 Ma) and the second during the early Paleogene (ca. 68–59 Ma). These two ages agree with the modelled thermal history of the Jinding reservoir. Combining the oil-before-ore timing sequence, high metal abundance of the bitumen, two negative sulfur isotope peaks of the sulfide and high S/C atomic ratio of the bitumen from the Jinding deposit, the oil-containing aqueous solutions were considered as one metal carrier during the hydrocarbon migration and accumulation; further, bacterial sulfate reduction and thermo-chemically induced sulfate reduction processes could have participated in the supply of reduced sulfur for the Pb Zn deposit precipitation. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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