Formalising an inversion methodology for reconstructing ice-sheet retreat patterns from meltwater channels: application to the British Ice Sheet

Glacial meltwater channels yield important information regarding patterns of palaeo-ice-sheet retreat. However, it is important to distinguish between channels formed at different positions in relation to the ice mass (e.g. lateral, subglacial). In Britain, whilst meltwater channels have been widely reported in the literature, such categorisation is often lacking. Here we develop an inversion methodology for extracting ice margin retreat patterns from meltwater channels. Diagnostic geomorphological criteria are presented, derived from published descriptions of meltwater channels form, by which a channel of unknown origin may be assigned to its appropriate category. These criteria are applied to channels recorded in the BRITICE CIS database of glacial landforms and we find most channels to be of lateral or subglacial origin. The categorisation of channels enables palaeomargin positions and the direction of retreat-stage ice flow to be approximated, and a preliminary reconstruction is made of fragments of the ice-sheet retreat pattern. Further mapping and integration of melt traces with other geomorphic data will permit a more complete palaeo-glaciological reconstruction of the last British Ice Sheet. Copyright (c) 2007 John Wiley & Sons, Ltd.