International Geologiical Congress - Oslo 2008


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GAH-01 Gas hydrates in oceanic and permafrost environments ? importance for energy, climate and geohazards


The Vigrid "Diapir" Field on the south Vøring Plateau, mid-Norwegian margin - mud diapirs or evacuation structures?


Skaug Mats Bjørndal, University of Bergen (Norway)
Berit Oline Hjelstuen, University of Bergen (Norway)
Haflidi Haflidason, University of Bergen (Norway)


For about fifteen years ago a ∼1100 km2 large field, comprising up to 75 m high and 200-500 m wide seabed mounds, were identified on the southern Vøring Plateau. These structures were, mainly based on 8.8 kHz recordings, interpreted to be mud diapirs related to Late Plio-Pleistocene differential sediment loading of Miocene-Oligocene biosiliceous oozes. However, this interpretation has lately been questioned; suggesting that the seabed features rather are evacuation structures related to slide events. It is essential to understand the generation of these features as, if related to diapirism, they may cause sediment instabilities which may pose a risk for the deployment of subsea installations on the seabed. In the PETROMAKS-project, "Gas hydrates on the Norwegian - Barents Sea - Svalbard margin" (GANS), coordinated by the University of Bergen, there is a focus on this topic, where we by the use of 3D and 2D seismic profiles, made available by the industry; and collections of sediment cores, multibeam echosounder (MBE) data and TOPAS high-resolution seismic profiles try to differentiate the extend, age and evolution of these seabed mounds. Here, we aim to present TOPAS data collected during the August 2007 cruise to the Vigrid "diapir" area with R/V G.O. SARS as well as 2D and MBE data made available from the industry.


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