2.0 Ga orogenic graphite deposits and associated 13C-enriched meta-carbonate rocks from South China Craton: Implications for global Lomagundi event

Li, Yihe; Satish-Kumar, M.; Kiran, S.; Wan, Chuanhui; Zheng, Jianping

doi:10.1016/j.gsf.2022.101409

Cited by 9 publications

(4 citation statements)

References 89 publications

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“…Anomalously high carbon burial played a crucial role in reducing friction strength and lubricating compressive deformation, which allowed crustal thickening to build Palaeoproterozoic mountain belts [83,84]. The earth's carbon reservoirs primarily consist of three principal sources: organic matter, sedimentary carbonates, and mantle-derived igneous carbon [14,16,85].…”

Section: Carbon Source Of the Tugeman Graphite Depositmentioning

confidence: 99%

“…Graphite deposits can be categorized into three types based on their primary host rock types: regional metamorphic type, contact metamorphic type, and hydrothermal type [88]. Regional metamorphism mainly occurs in the orogenic belt, so the study of the orogenic belt has become one of the focuses of the genetic research of graphite deposits [83,84]. The host rock of the graphite deposit in the Tugeman area comprises a series of metamorphic rocks formed by regional metamorphisms, such as schist, marble, and leptynite [55].…”

Section: Metallogenic Process Of the Tugeman Graphite Depositmentioning

confidence: 99%

“…After undergoing various metamorphic grades, graphite granules' Raman spectrum peaks change [82,104], primarily affecting the D1, G, and S1 bands as metamorphism intensifies [102]. The R1 and R2 ratios allow the determination of peak metamorphic conditions [82,101], as both R1 and R2 decrease with increasing metamorphic grade [26,84]. The R1 (<0.5) and R2 (<0.5) ratios of the C3 and C4 ore bodies indicate a higher degree of graphitization.…”

Section: Degree Of Metamorphism In Graphitementioning

confidence: 99%

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Genesis of the Graphite from the Tugeman Graphite Deposit, Xinjiang, China: Evidence for Carbon Isotope Refining by Fluids Associated with the Ductile Shear Zone

Li,

Hong,

Liu

et al. 2023

Minerals

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The Altun orogenic belt is situated along the northern boundary of the Tibetan Plateau. In this study, we present an analysis of the ore deposit, mineral composition, and carbon isotope signatures of the Tugeman graphite deposit within the Altun orogenic belt. The graphite in the Tugeman graphite deposit occurs within graphite-bearing schists and marble. Graphite enrichment is observed in the ductile shear zone. The carbon isotope values of graphite range between −18.90‰ and −10.03‰ (with an average value of −12.70‰). These values differ significantly from those observed in organic matter and marine carbonates, suggesting the occurrence of a mixing process involving reduced carbon fluid derived from biological organic material during regional metamorphism as well as a potential influx of oxidized carbon fluid from external sources. In addition, the metamorphic temperature of Tugeman graphite calculated from Raman spectroscopy is between 494 °C and 570 °C, which indicates that the disordered material is transformed from greenschist-amphibolite facies metamorphism to moderate-crystalline graphite. Combining the geological and carbon isotope characteristics of the Tugeman graphite deposit, we argue that the Tugeman graphite deposit is a regional metamorphic graphite deposit of biogenic origin, and during the late stage of metamorphism, it underwent interaction with fluids.

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Section: Carbon Source Of the Tugeman Graphite Depositmentioning

confidence: 99%

Section: Metallogenic Process Of the Tugeman Graphite Depositmentioning

confidence: 99%

Section: Degree Of Metamorphism In Graphitementioning

confidence: 99%

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Genesis of the Graphite from the Tugeman Graphite Deposit, Xinjiang, China: Evidence for Carbon Isotope Refining by Fluids Associated with the Ductile Shear Zone

Li,

Hong,

Liu

et al. 2023

Minerals

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“…A major criticism of the canonical LJE model is the lack of geological evidence for organic-rich rocks in the Palaeoproterozoic era 12,13,14 . However, the global occurrence (Figure 1A) of graphite-rich rocks chrono-correlated with the LJE reinforces the idea that large amounts of organic matter were buried during this time interval 15 .…”

Section: Introductionmentioning

confidence: 99%

The origin and fate of organic carbon in graphite-manganese bearing rocks and implications for the Lomagundi-Jatuli Event

Santos,

Amaral,

Filho

et al. 2024

Preprint

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Our study helps to unravel the complexity of the Lomagundi-Jatuli event, the largest and longest positive carbon isotope excursion ever recorded on the Earth's surface, by providing a unique view of Paleoproterozoic graphitic rocks from the Borborema province of Northeastern Brazil. Through detailed mineralogical, textural, chemical and isotopic analyses, we bring a new perspective that challenges existing views of the global impact of the Lomagundi-Jatuli event. Graphite crystals with distinctive textural features occur in association with silicate and oxidised manganese ores, manganese quartzites, garnetites, and gneisses. The graphites were crystallised at temperatures up to 634ºC, consistent with amphibolite facies metamorphism, according to Raman thermometry. An average carbon content of 2.1 wt%, with δ13C values ranging from -15.0 to -21.5‰, is indicated by whole-rock geochemistry and carbon isotopic composition. Based on these results, our study proposes that these graphitic rocks may represent remnants of organic matter, possibly derived from bacterial biomass associated with manganese-rich sediments, preserved under reducing environmental conditions. Biological mediation on the origin of silicates is suggested by the close relationship between reduced manganese silicates and graphite. These constraints indicate that Paleoproterozoic graphite-rich rocks represent an important but overlooked reservoir of organic carbon that was partially degassed during the metamorphism of organic-rich sequences. Overall, this research highlights the complex interplay between organic carbon, manganese-rich rocks and Earth's evolutionary processes during the Lomagundi-Jatuli event.

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Identification of carbonates with high positive carbon isotope excursion from the Liaohe Group in the northeastern North China Craton and implications for the Lomagundi-Jatuli Event

Wang,

Zhang,

Wang

et al. 2024

Sci. China Earth Sci.

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2.0 Ga orogenic graphite deposits and associated 13C-enriched meta-carbonate rocks from South China Craton: Implications for global Lomagundi event

Cited by 9 publications

References 89 publications

Genesis of the Graphite from the Tugeman Graphite Deposit, Xinjiang, China: Evidence for Carbon Isotope Refining by Fluids Associated with the Ductile Shear Zone

Genesis of the Graphite from the Tugeman Graphite Deposit, Xinjiang, China: Evidence for Carbon Isotope Refining by Fluids Associated with the Ductile Shear Zone

The origin and fate of organic carbon in graphite-manganese bearing rocks and implications for the Lomagundi-Jatuli Event

Identification of carbonates with high positive carbon isotope excursion from the Liaohe Group in the northeastern North China Craton and implications for the Lomagundi-Jatuli Event

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