The last Scottish ice‐sheet: facts and speculative discussion

Abstract

Evidence relating to the extent of the last (Late Devensian) Scottish ice‐sheet is critically discussed, particular attention being given to the limitations of some radiocarbon dates and incorrect inferences based on radiocarbon dates. It is suggested that the last Scottish and Scandinavian ice‐sheets were not confluent and that Orkney and NE Caithness may not have been covered by the last Scottish ice‐sheet. Ice‐sheet growth and decay are considered in relation to possible positions of the oceanic and atmospheric polar fronts: implications are that much the greater part of ice‐sheet decay resulted from inadequate snowfall and that the maximal limits of the last ice‐sheet may not have been synchronous. Ice‐sheet calving may have resulted in an independent ice mass over the Outer Hebrides. It is suggested that most of the bed of the Central North Sea became land during the Late Devensian and that a large delta existed in the eastern part of this area. It is also suggested that the buried and infilled channels of this eastern area, which are normally interpreted as tunnel valleys, are shallow delta channels whose present depth is due to delta subsidence