CAGE13-5 Cruise Report: Investigation of glacial geomorphology in the Storfjordrenna.

Abstract

The course GEO‐8144/3144 Marine geology and geophysics cruise, taught at the University of Tromsø, is part of the obligatory courses to be completed by PhD students affiliated with the AMGG research school and yields 5 credits (ECTS). Participants include scientific staff and students.
 This cruise was conducted within the framework of
 
 the Norwegian Science Council (NFR) project Glaciations in the Barents Sea area (GlaciBar) and
 the trainee school in Arctic Marine Geology and Geophysics (AMGG) financed by the University of Tromsø. The cruise was funded by AMGG.
 
 The main target areas are the Storfjordbanken and Storfjordrenna south of Svalbard. The cruise addressed marine glacigenic processes of the areas, with a focus on the last glacial-interglacial cycle in order to reconstruct in a more detail way the retreat of the Barents Sea–Svalbard Ice Sheet.
 To collect data have been used different methods and instruments, which will be described in a more detailed way in chapter 3. Below here there is only an overview:
 
 Multibeam echo sounder: Sound-wave beams are transmitted in a fan perpendicular to the ship track from a hull-mounted echo sounder. Produces high-resolution seafloor bathymetry.
 Chirp: High-resolution acoustic profiling.
 CTD (Conductivity, Temperature, Depth): Sensors installed in a frame measure CTD properties of the water column. Generally used for oceanographic studies, but here mainly to calibrate the multibeam data from calculated velocities.
 2D seismic: GI airguns and hydrophone cable (streamer).
 Sediment coring: Gravity coring.
 Gas sample collection.
 
 The targeted study area is under-explored compared to similar areas (Bjørnøyrenna) in the SW Barents Sea. The study areas in the Storfjordrenna and Stordfjorbanken are shown. Several different features have been identified on the seafloor, like MSGLs, grounding zone wedges, flares, pockmarks and ploughmarks. All these features will be described in detail in chapter 4.
 In addition, 9 gravity cores were acquired in areas likely to provide information on the timing of the formation of the sediment accumulation. The specific core locations were chosen based on information from multibeam swath bathymetry and chirp data. Furthermore, gas samples were collected from the cores from pockmarks and will be analyzed later.
 The new results add new detailed data regarding the deglaciation of the Storfjorden trough. Glacial geomorphologic features similar to the ones in Bjørnøyrenna were discovered. The observation of gas flares were the first such discovery in the northern Barents Sea. The discovery of flares and pockmarks might have a big impact on future petroleum exploration activities in the region.
 The cruise may be known as: HH_2013_GEO_8144_3144