Genetic link between Mississippi Valley-Type (MVT) Zn-Pb mineralization and hydrocarbon accumulation in the Nanmushu, northern margin of Sichuan Basin, SW China

Genetic relationship between the Maoping Pb-Zn deposit and paleo-oil reservoir in the northern Yunnan-Guizhou depression: Evidence from bitumen trace elements and the in-situ sulfur isotope of pyrite associated with bitumen

“…The content of Zn in bitumen from the Huayuan lead-zinc mine in Hunan province of China is 200-20,248 ppm . The contents of Pb and Zn in bitumen in the Nanmushu lead-zinc deposit in northwest Sichuan Basin are 15.6-2,600 ppm (average 461 ppm, n = 10, Huang et al, 2021) and 129.9->10,000 ppm (average > 4,123 ppm, n = 10, Huang et al, 2021); in the Xuequ lead-zinc deposit in southwestern Sichuan Basin, they are 20-287 ppm and 15-5,370 ppm (Tan et al, 2021); and they are 15.3-161.6 ppm and 129.9-1171.5 ppm in the Mayuan lead-zinc deposit in northern Sichuan Basin (Tan et al, 2021). These values are much higher than the Pb and Zn content in Pb and Zn ore-forming fluids (2.0 and 1.3 ppm, respectively; Sverjensky, 1984), suggesting that not only oil plays the role of metal element transport medium, but also that the hydrocarbon fluid may be the ore-forming fluid, and the metal elements and oil have the same characteristics in source, transport and aggregation (Tan et al, 2021).…”

“…In addition, black mudstone also is considered to an important metal source for Pb-Zn deposits in the area, such as Jinshachang lead-zinc deposit (Zhou et al, 2015). Recent studies show that for the MVT lead-zinc deposits which have bitumen with abundant Pb and Zn elements, the parent rocks of bitumen (source rocks) are also considered to be one of the metallogenic metal sources, e.g., Nanmushu and Wusihe Pb-Zn deposits in Sichuan Basin (Huang et al, 2021;Wang et al, 2022).…”

“…It is well known that with the increase in the burial depth of source rock, organic matter in source rock begins to mature and forms crude oil. If the metal elements in the source rock migrate together with crude oil from the source rock, this will enrich the ore-forming metal elements in oil (Huang et al, 2021). Thus, whether the bitumen from the reservoir is rich in metal elements becomes a direct way to test this possibility.…”

“…In many cases, hydrocarbons migrate separately from or together with the mineralizing fluids within sedimentary basins and are deposited in the form of petroleum or solid bitumen in the vicinity of sulfides (Püttmann et al, 1988;Manning and Gize, 1993;Kozłowski et al, 1995;Spangenberg and Herlec, 2006;Rieger et al, 2008;Williford et al, 2011;Lan et al, 2021). Therefore, at present, a common phenomenon is that many lead-zinc deposits in the world are closely paragenetic or spatially associated with oil and gas reservoirs (Kesler et al, 1994;Lin, 1995;Sicree and Barnes, 1996;Chen et al, 2008;Wu et al, 2013a;Fang et al, 2016;Huang et al, 2019;Huang et al, 2021;Lan et al, 2021;Wang et al, 2022). The closely spatial connection between Pb-Zn deposits and paleo-oil reservoirs and the development of high precision testing technology has added to the deeply research on the relationship between organic matter (crude oil, solid bitumen, methane and/or ethane, etc.)…”

“…and mineralization, creating a hot spot in the study of mineral deposits (Li et al, 2021). Oil and gas can actively participate in the mineralization of metal deposits and play an important role in the formation of ore deposits, which primarily as follows: 1) the preenrichment of metals (Chen et al, 2002); 2) activation, migration and enrichment of metallogenetic elements (Girodano, 1985;Li et al, 2002;Saintilan et al, 2019;Sanz-Robinson and Williams-Jones, 2019); 3) provides a large amount of reduced sulfur (H 2 S/HS − ) for mineralization (Gu et al, 2012;Cheng et al, 2021;Huang et al, 2021;Wang et al, 2022); 4) organic acids are produced to dissolve carbonate rocks to provide ore storage space, and organic carbon is provided to participate in the precipitation of hydrothermal carbonate (Liu and Zheng, 2000;Liu et al, 2016); 5) to create the physical and chemical conditions necessary for mineralization .…”