Malangsdjupet: a cross-shelf trough on the North Norwegian margin

Abstract

Cross-shelf troughs, linked to the presence of fast-flowing ice streams, are a common feature of high-latitude shelves (Batchelor & Dowdeswell 2014). On the North Norwegian shelf (Fig. 1a–e), ice advanced westwards as the Scandinavian Ice Sheet expanded during full-glacial conditions on a number of occasions during the Quaternary (Rise et al. 2005). As ice flowed out from the crystalline bedrock of Norway, it eroded deep cross-shelf troughs in the shelf sediments beyond and left evidence of former rapid flow in the form of streamlined landforms such as mega-scale glacial lineations (Ottesen et al. 2005). Glacial sediment was delivered to a submarine fan on the continental slope that built out from the mouth of the trough. Malangsdjupet on the North Norwegian margin (Fig. 1e) provides an example of a well-developed cross-shelf trough where there is clear evidence of occupation by an ice stream that drained the interior of the Scandinavian Ice Sheet under full-glacial conditions. Fig. 1. ( a ) MAREANO swath-bathymetry shaded-relief map of the Malangsdjupet cross-shelf trough, North Norway. Acquisition systems Kongsberg EM710 (70–100 kHz), EM1002 (95 kHz) and EM3000 (300 kHz). Grid-cell size 50 m. TMF, trough-mouth fan; GZW, grounding-zone wedge. ( b ) Sub-bottom profile across the northern lateral …