Glacitectonic landforms and processes on the Norwegian continental shelf were first described by Sættem (1990). Over the past two decades, multibeam bathymetry has revealed a number of glacitectonic features. Three-dimensional (3D) seismic data have also shown that glacitectonic processes are more widespread than previously thought (Andreassen et al. 2004). Hill–hole pairs have been observed mainly on land (Moran et al. 1980; Aber & Ber 2007) and few examples are known from previously glaciated continental shelves (Fig. 1). Hill–hole pair sedimentology and structural geology have been examined at the terrestrial margin of the former North American Ice Sheet (Moran et al. 1980). The hills comprise thrust-block moraines apparently formed at former ice margins and the holes are source areas. Hill–hole axes are sub-parallel to inferred ice-flow direction. Compressive subglacial stresses, leading to tectonism, are thought to be induced by basal freezing close to thin ice-sheet margins (Moran et al. 1980).
Hill–hole pairs on the continental shelf off Norway. (a) Multibeam image of the Steinbitryggen–Sopphola hill–hole pair (S-S) and two less well-defined glacitectonic pairs (B, C) on Tromsøflaket bank. (b) Multibeam image of Hesteskoen hill–hole pair on easternmost Trænabanken. Acquisition system for (a) …
Please note that if you are logged into the Lyell Collection and attempt to access content that is outside of your subscription entitlement you will be presented with a new login screen. You have the option to pay to view this content if you choose. Please see the relevant links below for further assistance.