New data for the Last Glacial Maximum in Great Britain and Ireland: a Scottish perspective on the paper by Bowen et al. (2002)

Abstract

The recent reconstruction by Bowen et al. (2002) of the history of the last British and Irish Ice sheet (BIIS) at the Last Glacial Maximum (LGM) resumes a debate over the extent and behaviour of the last Scottish Ice Sheet (ScIS) that extends back over 20 years (Sutherland, 1984). The ScIS at the LGM is seen as restricted in extent, with ice-free peripheral areas that include Buchan, Caithness, Orkney, Shetland, together with extensive areas of the North Sea and the Hebridean and Shetland shelves (Fig. 1). Moreover, the BIIS is viewed as a long-lived, if dynamic feature throughout Oxygen Isotope Stages 4-2. We consider it unfortunate that Bowen et al. (2002) do not refer to much long-standing and recent work in Scotland that indicates extensive glaciation at the LGM yet a ScIS of very limited extent around 30 ka BP. This note seeks to redress that balance. ‘Uncorrected’ radiocarbon ages rather than calibrated ages are referred to below, because calibration before 17 cal ka BP is uncertain (van der Plicht, 2002). A reservoir age of ca. 400 years has been applied to marine C ages, though we recognise that this may be in error prior to ca. 12.5 ka BP (cf. Voelker et al., 1998).