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Pape, Thomas; Malnati, Janice; Bohrmann, Gerhard (2019): Physical properties, gas compositon, and δ¹³C DIC measured on sediment cores from an active pockmark on Vestnesa Ridge, Arctic Ocean. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.905864 (dataset in review), Supplement to: Pape, Thomas; Bünz, S; Hong, Wei-Li; Torres, Marta E; Riedel, Michael; Panieri, Giuliana; Lepland, A; Hsu, Chieh-Wei; Wintersteller, Paul; Wallmann, Klaus; Schmidt, Christopher; Yao, Haoyi; Bohrmann, Gerhard (accepted): Origin and transformation of light hydrocarbons ascending at an active pockmark on Vestnesa Ridge, Arctic Ocean. Journal of Geophysical Research: Solid Earth, https://doi.org/10.1029/2018JB016679

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Abstract:
We report on the geochemistry of hydrocarbons and pore waters down to 62.5 mbsf, collected by drilling with the MARUM‐MeBo70 and by gravity coring at the Lunde pockmark in the Vestnesa Ridge. Our data document the origin and transformations of volatiles feeding gas emissions previously documented in this region. Gas hydrates are present where a fracture network beneath the pockmark focusses migration of thermogenic hydrocarbons characterized by their C1/C2+ and stable isotopic compositions (δ2H‐CH4, δ13C‐CH4). Measured geothermal gradients (~80°C km‐1) and known formation temperatures (>70°C) suggest that those hydrocarbons are formed at depths >800 mbsf.
A combined analytical/modeling approach, including concentration and isotopic mass balances, reveals that pockmark sediments experience diffuse migration of thermogenic hydrocarbons. However, at sites without channeled flow this appears to be limited to depths > ~50 mbsf. At all sites we document a contribution of microbial methanogenesis to the overall carbon cycle that includes a component of secondary carbonate reduction (CR) – i.e. reduction of dissolved inorganic carbon (DIC) generated by anaerobic oxidation of methane (AOM) in the uppermost methanogenic zone. AOM and CR rates are spatially variable within the pockmark and are highest at high‐flux sites. These reactions are revealed by δ13C‐DIC depletions at the sulfate‐methane interface at all sites. However, δ13C‐CH4 depletions are only observed at the low methane flux sites because changes in the isotopic composition of the overall methane pool are masked at high‐flux sites. 13C‐depletions of TOC suggest that at seeps sites, methane‐derived carbon is incorporated into de novo synthesized biomass.
Coverage:
Median Latitude: 79.006244 * Median Longitude: 6.914585 * South-bound Latitude: 78.996767 * West-bound Longitude: 6.904083 * North-bound Latitude: 79.008433 * East-bound Longitude: 6.963467
Date/Time Start: 2016-08-02T16:54:00 * Date/Time End: 2016-08-29T04:39:00
Size:
26 datasets

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Datasets listed in this publication series

  1. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5) and stable carbon isotopic composition of methane (δ¹³C-CH4) in core GeoB21610-1. https://doi.pangaea.de/10.1594/PANGAEA.905812
  2. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5) and stable carbon isotopic composition of methane (δ¹³C-CH4) in core GeoB21637-1. https://doi.pangaea.de/10.1594/PANGAEA.905810
  3. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5), stable carbon isotopic composition of methane (δ¹³C-CH4), and stable hydrogen isotopic composition of methane (d2H-CH4) in core GeoB21609-2. https://doi.pangaea.de/10.1594/PANGAEA.905803
  4. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5), stable carbon isotopic composition of methane (δ¹³C-CH4), and stable hydrogen isotopic composition of methane (d2H-CH4) in core GeoB21612-1. https://doi.pangaea.de/10.1594/PANGAEA.905805
  5. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5), stable carbon isotopic composition of methane (δ¹³C-CH4), and stable hydrogen isotopic composition of methane (d2H-CH4) in core GeoB21616-1. https://doi.pangaea.de/10.1594/PANGAEA.905814
  6. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5), stable carbon isotopic composition of methane (δ¹³C-CH4), and stable hydrogen isotopic composition of methane (d2H-CH4) in core GeoB21619-1. https://doi.pangaea.de/10.1594/PANGAEA.905808
  7. Pape, T; Malnati, J; Bohrmann, G (2019): Hydrocarbon composition (C1/(C2-C5), stable carbon isotopic composition of methane (δ¹³C-CH4), and stable hydrogen isotopic composition of methane (d2H-CH4) in core GeoB21621-1. https://doi.pangaea.de/10.1594/PANGAEA.905815
  8. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21612-1. https://doi.pangaea.de/10.1594/PANGAEA.905769
  9. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21616-1. https://doi.pangaea.de/10.1594/PANGAEA.905771
  10. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21621-1. https://doi.pangaea.de/10.1594/PANGAEA.905773
  11. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21605-1. https://doi.pangaea.de/10.1594/PANGAEA.905768
  12. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21613-1. https://doi.pangaea.de/10.1594/PANGAEA.905770
  13. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21619-1. https://doi.pangaea.de/10.1594/PANGAEA.905772
  14. Pape, T; Malnati, J; Bohrmann, G (2019): Physical properties of sediments and stable carbon isotopic composition of organic matter in core GeoB21637-1. https://doi.pangaea.de/10.1594/PANGAEA.905774
  15. Pape, T; Malnati, J; Bohrmann, G (2019): Stable carbon isotopic composition of methane (δ¹³C-CH4) in core GeoB21601-1. https://doi.pangaea.de/10.1594/PANGAEA.905801
  16. Pape, T; Malnati, J; Bohrmann, G (2019): Stable carbon isotopic composition of methane (δ¹³C-CH4) in core GeoB21605-1. https://doi.pangaea.de/10.1594/PANGAEA.905802
  17. Pape, T; Malnati, J; Bohrmann, G (2019): Stable carbon isotopic composition of methane (δ¹³C-CH4) in core GeoB21638-1. https://doi.pangaea.de/10.1594/PANGAEA.905811
  18. Pape, T; Malnati, J; Bohrmann, G (2019): Stable carbon isotopic composition of methane (δ¹³C-CH4), and stable hydrogen isotopic composition of methane (d2H-CH4) in core GeoB21613-1. https://doi.pangaea.de/10.1594/PANGAEA.905813
  19. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21637-1. https://doi.pangaea.de/10.1594/PANGAEA.905886
  20. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21601-1. https://doi.pangaea.de/10.1594/PANGAEA.905855
  21. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21605-1. https://doi.pangaea.de/10.1594/PANGAEA.905856
  22. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21610-1. https://doi.pangaea.de/10.1594/PANGAEA.905857
  23. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21612-1. https://doi.pangaea.de/10.1594/PANGAEA.905858
  24. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21613-1. https://doi.pangaea.de/10.1594/PANGAEA.905859
  25. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21619-1. https://doi.pangaea.de/10.1594/PANGAEA.905860
  26. Torres, ME; Pape, T; Hong, W-L et al. (2019): Stable carbon isotopic composition of dissolved inorganic carbon (δ¹³C-DIC) in sediment core GeoB21621-1. https://doi.pangaea.de/10.1594/PANGAEA.905861