| Popis: |
Summary Glacial landforms identified in seismic 3D and multibeam data of the Barents Sea have improved the knowledge about past glaciations and associated geohazards. High-resolution P-Cable 3D seismic data were acquired in this area with an inline separation of 6 m, a source frequency range of 5–350 Hz and an source-receiver offset range of 120–160 m. Seabed images derived from the P-Cable data show an increased resolution and sharpness compared to images from conventional 3D seismic and multibeam echosounder data. High-resolution images of the buried Upper Regional Unconformity (URU) were derived from the P-Cable data, revealing previously unrecognized structures such as hill-hole pairs and rhombohedral and transverse ridges. These observations indicate different subglacial thermal regimes, the presence of permafrost, and a strong link with variations in the underlying geology. No reflections are imaged within the intraglacial sediment package in the conventional seismic data. However, reflections interpreted as the top of a shear margin moraine, shear planes, mass transport deposits, and soft beds are visible in the P-Cable data. Meter-scale glacial landforms and layers identified in the P-Cable cubes comprise new information about glacier dynamics, fluid flow, and faults, which are valuable for geotechnical and geohazard evaluations of offshore infrastructure. |
