Blar i forfatter "Semenov, Peter"

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    • Methane release from pingo-like features across the South Kara Sea shelf, an area of thawing offshore permafrost 

      Serov, Pavel; Portnov, Aleksei D; Mienert, Jurgen; Semenov, Peter; Ilatovskaya, Polonia (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-07-16)
      The Holocene marine transgression starting at ~19 ka flooded the Arctic shelves driving extensive thawing of terrestrial permafrost. It thereby promoted methanogenesis within sediments, the dissociation of gas hydrates, and the release of formerly trapped gas, with the accumulation in pressure of released methane eventually triggering blowouts through weakened zones in the overlying and thinned ...

    • Offshore permafrost decay and massive seabed methane escape in water depths >20 m at the South Kara Sea shelf 

      Portnov, Alexey; Mienert, Jurgen; Cherkashov, Georgy; Rekant, Pavel; Semenov, Peter; Serov, Pavel; Vanshtein, Boris; Smith, Andrew James (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-07-14)
      Since the Last Glacial Maximum (~19 ka), coastal inundation from sea-level rise has been thawing thick subsea permafrost across the Arctic. Although subsea permafrost has been mapped on several Arctic continental shelves, permafrost distribution in the South Kara Sea and the extent to which it is acting as an impermeable seal to seabed methane escape remains poorly understood. Here we use >1300 km ...

    • Shallow carbon storage in ancient buried thermokarst in the South Kara Sea 

      Portnov, Aleksei D; Mienert, Jürgen; Winsborrow, Monica; Andreassen, Karin; Vadakkepuliyambatta, Sunil; Semenov, Peter; Gataullin, Valery (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-25)
      Geophysical data from the South Kara Sea reveal U-shaped erosional structures buried beneath the 50–250 m deep seafloor of the continental shelf across an area of ~32 000 km<sup>2</sup>. These structures are interpreted as thermokarst, formed in ancient yedoma terrains during Quaternary interglacial periods. Based on comparison to modern yedoma terrains, we suggest that these thermokarst features ...