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The Source of Organic Matter and Its Role in Producing Reduced Sulfur for the Giant Sediment-Hosted Jinding Zinc-Lead Deposit, Lanping Basin, Yunnan, Southwest China
- Source :
- Economic Geology. 116:1537-1560
- Publication Year :
- 2021
- Publisher :
- Society of Economic Geologists, 2021.
-
Abstract
- The Jinding deposit, located in the northern part of Lanping basin in southwest China, is the second largest Zn-Pb deposit in China and the third largest Mississippi Valley-type deposit identified globally. The deposit consists of several large tabular orebodies within the Jinding dome. Two stages of sulfide mineralization (sphalerite, galena, and pyrite) are identified, which are mainly hosted in the siliciclastic strata of Early Cretaceous and Paleocene age. The early sulfide minerals are mostly fine grained ( The δ34S values, ranging from –30 to –10‰ for the fine-grained and disseminated sulfide minerals and from –24.50 to –16.27‰ for the solid bitumen in the early (main) mineralization stage, suggest that H2S was generated by microbial sulfate reduction. We propose that this occurred in the Triassic strata prior to or during migration of hydrocarbons to the Jinding dome to form a H2S-enriched paleo-oil reservoir. This hypothesis is supported by the similarity of the δ34S values (–27.62 to –17.38‰) of solid bitumen in the Sanhedong Formation (the source rocks) to that of bitumen in the ores. The late-ore sulfide, however, displays significantly higher δ34S values, ranging from –8 to 0‰. We propose that the H2S of this stage was mainly generated by thermochemical sulfate reduction as a result of the interaction between hydrocarbons, sulfate, and hydrothermal fluid. The hydrocarbons were oxidized into bitumen that has δ34S values from –7.38 to –4.61‰.
- Subjects :
- chemistry.chemical_classification
010504 meteorology & atmospheric sciences
Geochemistry
Sediment
chemistry.chemical_element
Geology
Zinc
Structural basin
010502 geochemistry & geophysics
01 natural sciences
Sulfur
Geophysics
Lead (geology)
chemistry
Geochemistry and Petrology
Economic Geology
Organic matter
China
0105 earth and related environmental sciences
Subjects
Details
- ISSN :
- 15540774 and 03610128
- Volume :
- 116
- Database :
- OpenAIRE
- Journal :
- Economic Geology
- Accession number :
- edsair.doi...........75c1f956c1a458eac9441f05120b4191