Blar i forfatter "Bohrmann, Gerhard"

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    • A 160,000-year-old history of tectonically controlled methane seepage in the Arctic 

      Himmler, Tobias; Sahy, Diana; Martma, Tõnu; Bohrmann, Gerhard; Plaza-Faverola, Andreia; Bünz, Stefan; Condon, Daniel J.; Knies, Jochen; Lepland, Aivo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-07)
      The geological factors controlling gas release from Arctic deep-water gas reservoirs through seabed methane seeps are poorly constrained. This is partly due to limited data on the precise chronology of past methane emission episodes. Here, we use uranium-thorium dating of seep carbonates sampled from the seabed and from cores drilled at the Vestnesa Ridge, off West Svalbard (79°N, ~1200 m water ...

    • Origin and transformation of light hydrocarbons ascending at an active pockmark on Vestnesa Ridge, Arctic Ocean 

      Pape, Thomas; Buenz, Stefan; Hong, Wei-Li; Torres, Marta E.; Riedel, Matthias; Panieri, Giuliana; Lepland, Aivo; Hsu, Chieh Wei; Wintersteller, Paul; Wallmann, Klaus; Schmidt, Christopher; Yao, Haoyi; Bohrmann, Gerhard (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-25)
      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 ...

    • Shallow Gas Hydrate Accumulations at a Nigerian Deepwater Pockmark—Quantities and Dynamics 

      Pape, Thomas; Ruffine, Livio; Hong, Wei-Li; Sultan, Nabil; Riboulot, Vincent; Peters, Carl A.; Kölling, Martin; Zabel, Matthias; Garziglia, Sébastien; Bohrmann, Gerhard (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-06)
      The evolution of submarine pockmarks is often related to the ascent of fluid from the subsurface. For pockmarks located within the gas hydrate stability zone, methane oversaturation can result in the formation of gas hydrates in the sediment. An ~600 m‐wide sea floor depression in deep waters offshore Nigeria, Pockmark A, was investigated for distributions and quantities of shallow gas hydrates, ...