Coupled pyrite concentration and sulfur isotopic insight into the paleo sulfate–methane transition zone (SMTZ) in the northern South China Sea

Qi, Lin; Wang, Jiasheng; Taladay, Katie; Lu, Hongfeng; Hu, Gaowei; Sun, Fei; Lin, Rongxiao

doi:10.1016/j.jseaes.2015.11.001

Cited by 63 publications

(24 citation statements)

References 67 publications

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“…Recent studies have demonstrated that in rapidly depositing methane‐rich marine sedimentary environments, enrichment of CRS (δ 34 S CRS ) and molybdenum (Mo) can be used as proxies to identify paleo‐SMTZs and methane seepage events in marine sediments (Chen et al, ; Hu et al, ; Li et al, ; Lin et al, ; Peketi et al, , ). Negative correlation between CRS content and χ lf in sediment cores MD161/Stn8, MD161/Stn13, and NGHP‐01‐10D (Figure e; Badesab et al, ) suggests that magnetic tracking in combination with geochemical proxies (CRS, δ 34 S CRS , Mo) can be used to constrain paleo‐SMTZ and methane seepage events in marine sediments.…”

Section: Discussionmentioning

confidence: 99%

Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal

et al. 2019

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We evaluate the environmental magnetic, geochemical, and sedimentological records from three sediment cores from potential methane-hydrate bearing sites to unravel linkages between sedimentation, shale tectonics, magnetite enrichment, diagenesis, and gas hydrate formation in the Krishna-Godavari basin. Based on downcore rock magnetic variations, four sedimentary magnetic property zones (I-IV) are demarcated. A uniform band of enhanced magnetic susceptibility (zone III) appears to reflect a period of high-sedimentation events in the Krishna-Godavari basin. Highly pressurized sedimentary strata developed as a result of increased sedimentation that triggered the development of a fault system that provided conduits for upward methane migration to enter the gas hydrate stability zone, leading to the formation of gas hydrate deposits that potentially seal the fault system. Magnetic susceptibility fluctuations and the presence of iron sulfides in a magnetically enhanced zone suggest that fault system growth facilitated episodic methane venting from deeper sources that led to multiple methane seepage events. Pyrite formation along sediment fractures resulted in diagenetic depletion of magnetic signals and potentially indicates paleo sulfate-methane transition zone positions. We demonstrate that a close correlation between magnetic susceptibility and chromium reducible sulfur concentration can be used as a proxy to constrain paleomethane seepage events. Our findings suggest that the interplay between higher sedimentation events and shale tectonism facilitated fluid/gas migration and trapping and the development of the gas hydrate system in the Krishna-Godavari basin. The proposed magnetic mineralogical approach has wider scope to constrain the understanding of gas hydrate systems in marine sediments.

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Section: Discussionmentioning

confidence: 99%

Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal

et al. 2019

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“…+20‰) owing to quantitative consumption of porewater sulfate (Canfield et al, 2010;Sim et al, 2011;Antler et al, 2013;Borowski et al, 2013;Leavitt et al, 2013). Thus, a combination of high pyrite concentrations and strongly 34 S-enriched pyrite may be taken as indicators of enhanced methane fluxes within the SMTZ (e.g., Jørgensen et al, 2004;Peketi et al, 2012;Borowski et al, 2013;Lin et al, 2016). M A N U S C R I P T…”

Section: Size Distributions Of Framboidal Pyrite Within the Smtzmentioning

confidence: 99%

“…4). The concentration of pyrite at Site 2A was determined by two methods, handpicking pyrite using a binocular microscope and via the chromium reduction method, both of which demonstrated an unusually large abundance of pyrite (Lin et al, 2016). At Site 973-4, total sulfur (TS) (Zhang-J et al, 2014) and pyrite formation (Lin et al, 2015) also show a similar pattern in concentrations.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Enhanced framboidal pyrite formation related to anaerobic oxidation of methane in the sulfate-methane transition zone of the northern South China Sea

Wang

Algeo

et al. 2016

Marine Geology

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“…In environments characterized by low methane fluxes, the SMTZ is located deeper in the sediment column, with more restricted inputs from downward diffusing sulfate. In these environments, the sulfate replenishment rate from the above sub-surface sediment layers is generally lower than sulfate consumption rate at the SMTZ (Lin Q. et al, 2016). This effect can result in residual dissolved sulfate and associated hydrogen sulfide being characterized by a shift toward heavier sulfur isotopic compositions (Borowski et al, 1996;Jørgensen et al, 2004;Jørgensen and Parkes, 2010;Peketi et al, 2012Peketi et al, , 2015.…”

Section: The Utility Of Aom-related Indicators In Cold Seep Sedimentsmentioning

confidence: 99%

“…The circulation of methane-rich fluids can significantly alter the primary sulfur isotopic composition of marine sediments (Jørgensen et al, 2004;Lin Q. et al, 2016;Gong et al, 2018). In this study, we report an extensive set of data for total carbon (TC), total organic carbon (TOC), total nitrogen (TN), and total sulfur (TS), acid-insoluble carbon and sulfur isotope, chromium reducibility sulfur (CRS = FeS 2 , S° and remaining part of Fe 3 S 4 , Jørgensen et al, 2004) and δ 34 S CRS as well as carbon isotopes of TIC, on sediment cores collected from the Haima site, an active cold seep site recently discovered in the northeast of South China Sea (SCS; .…”

Section: Introductionmentioning

confidence: 99%

Using chemical compositions of sediments to constrain methane seepage dynamics: A case study from Haima cold seeps of the South China Sea

Wang

Niu

Dong

et al. 2018

Journal of Asian Earth Sciences

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Cold seeps frequently occur at the seafloor along continental margins. The dominant biogeochemical processes at cold seeps are the combined anaerobic oxidation of methane and sulfate reduction, which can significantly impact the global carbon and sulfur cycles. The circulation of methane-rich fluids at margins is highly variable in time and space, and assessing past seepage activity requires the use of specific geochemical markers. In this study, we report multiple sedimentary proxy records for three piston gravity cores (QDN-14A, QDN-14B, and QDN-31) from the Haima seep of the South China Sea (SCS). By combining total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN), total sulfur (TS), acid insoluble carbon and sulfur isotope (δ13Corganic carbon and δ34Sacid-insoluble), and δ34S values of chromium reducibility sulfur (δ34SCRS), as well as carbon isotopes of TIC (δ13CTIC) in sediments, our aim was to provide constraints on methane seepage dynamics in this area. We identified three sediment layers at about 260-300 cm, 380-420 cm and 480-520 cm sediment depth, characterized by particular anomalies of low δ13CTIC values and high TS content, high TS and CRS contents, and high δ34Sacid-insoluble and δ34SCRS values, respectively. On this basis, we propose that these sediment horizons correspond to distinct methane release events preserved in the sediment record. While the exact mechanisms accounting for the presence (or absence) of these particular geochemical signals in the sediment are not known, we propose that they correspond to variations in methane flux and their duration through time. Overall, our results suggest that sedimentary carbon and sulfur and their isotopes are useful tracers for better understanding of methane seepage dynamics over time. Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

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Coupled pyrite concentration and sulfur isotopic insight into the paleo sulfate–methane transition zone (SMTZ) in the northern South China Sea

Cited by 63 publications

References 67 publications

Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal

Magnetic Mineralogical Approach for the Exploration of Gas Hydrates in the Bay of Bengal

Enhanced framboidal pyrite formation related to anaerobic oxidation of methane in the sulfate-methane transition zone of the northern South China Sea

Using chemical compositions of sediments to constrain methane seepage dynamics: A case study from Haima cold seeps of the South China Sea

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