• 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 ...
    • An Arctic natural oil seep investigated from space to the seafloor 

      Panieri, Giuliana; Argentino, Claudio; Ramalho, Sofia P.; Vulcano, Francesca; Savini, Alessandra; Fallati, Luca; Brekke, Trond; Galimberti, Giulia; Riva, Federica; Balsa, João; Eilertsen, Mari Heggernes; Stokke, Runar; Steen, Ida Helene; Sahy, Diana; Kalenitchenko, Dimitri Stanislas Desire; Bünz, Stefan; Mattingsdal, Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-19)
      Due to climate change, decreasing ice cover and increasing industrial activities, Arctic marine ecosystems are expected to face higher levels of anthropogenic stress. To sustain healthy and productive ocean ecosystems, it is imperative to build baseline data to assess future changes. Herein, a natural oil seep site offshore western Svalbard (Prins Karls Forland, PKF, 80–100 m water depth), discovered ...
    • Biogeochemistry and timing of methane-derived carbonate formation at Leirdjupet fault complex, SW Barents sea 

      Argentino, Claudio; Lee, Amicia; Fallati, Luca; Sahy, Diana; Birgel, Daniel; Peckmann, Jörn; Bünz, Stefan; Panieri, Giuliana (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-25)
      The origin of modern seafloor methane emissions in the Barents Sea is tightly connected to the glacio-tectonic and oceanographic transformations following the last ice age. Those regional events induced geological structure re-activation and destabilization of gas hydrate reservoirs over large areas of the European continental margins, sustaining widespread fluid plumbing systems. Despite the ...
    • Discharge of Meteoric Water in the Eastern Norwegian Sea since the Last Glacial Period 

      Hong, Wei-Li; Lepland, Aivo; Himmler, Tobias; Kim, Ji‐Hoon; Chand, Shyam; Sahy, Diana; Solomon, Evan A.; Rae, James W. B.; Martma, Tõnu; Nam, Seung‐Il; Knies, Jochen (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-07-03)
      Submarine groundwater discharge could impact the transport of critical solutes to the ocean. However, its driver(s), significance over geological time scales, and geographical coverage are poorly understood. We characterize a submarine groundwater seep from the continental slope off northern Norway where substantial amount of meteoric water was detected. We reconstruct the seepage history from ...
    • Protracted post-glacial hydrocarbon seepage in the Barents Sea revealed by U–Th dating of seep carbonates 

      Himmler, Tobias; Wagner, Doris; Sahy, Diana; Vadakkepuliyambatta, Sunil; Chand, Shyam; Martma, Tõnu; Kirsimäe, Kalle; Mattingsdal, Rune; Panieri, Giuliana; Bünz, Stefan; Condon, Daniel J.; Knies, Jochen Manfred; Lepland, Aivo (Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-01)
      The hydrocarbon seepage chronology during deglaciation across the formerly glaciated Barents Sea was established using uranium-thorium (U–Th) dating of seep carbonates. Seep carbonates were sampled with remotely operated vehicles (ROV) from the seafloor at three active hydrocarbon seeps (water depth 156–383 m), located in the north-west (Storfjordrenna), north-central (Storbanken High), and south-west ...
    • Timescales of methane seepage on the Norwegian margin following collapse of the Scandinavian Ice Sheet 

      Cremiere, Antoine; Lepland, Aivo; Chand, Shyam; Sahy, Diana; Condon, Daniel J.; Noble, Stephen R.; Martma, Tõnu; Thorsnes, Terje; Sauer, Simone; Brunstad, Harald (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-11)
      Gas hydrates stored on continental shelves are susceptible to dissociation triggered by environmental changes. Knowledge of the timescales of gas hydrate dissociation and subsequent methane release are critical in understanding the impact of marine gas hydrates on the ocean–atmosphere system. Here we report a methane efflux chronology from five sites, at depths of 220–400 m, in the southwest Barents ...
    • U-Th chronology and formation controls of methane-derived authigenic carbonates from the Hola trough seep area, northern Norway 

      Sauer, Simone; Knies, Jochen; Lepland, Aivo; Sahy, Diana; Martma, Tõnu; Noble, Stephen R.; Schönenbergerb, Jasmin; Klug, Martin; Schubert, Carsten J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-10-20)
      We investigated methane-derived authigenic carbonate (MDAC) crusts and nodules from a cold seep site on the northern Norwegian continental shelf in ca. 220 m water depth to determine the timing and mode of their formation. Gas bubbling observed during remotely operated vehicle (ROV)-assisted sampling of MDAC crusts revealed ongoing seep activity. Authigenic carbonates were present as crusts on the ...