Discussion of ‘Late Devensian palaeoenvironmental changes in the sea area adjacent to Islay, SW Scotland: implications for the deglacial history of the island’ by J.D. Peacock, Scottish Journal of Geology, 44, 183–190

摘要

A.G. Dawson writes: The paper by Peacock (2008) represents a valuable contribution to our understanding of the Late Quaternary history of Islay in particular and the SW Scottish Hebrides as a whole. As part of the conclusions based on examination and dating of three cores (two from Loch Indaal and one from between SE Islay and SE Jura) Peacock argues that his interpretation is difficult to reconcile with the view presented by this author that the limit of the Late Devensian ice sheet lay SW–NE across Islay and is represented, in part, by the Central Islay moraine (Dawson 1982). The latter view is not a new one. For example, Sissons (1981) argued on several grounds (mostly on the basis of raised shoreline evidence) that the last (Late Devensian) Scottish ice sheet may have terminated amidst the Inner Hebridean islands. Of course, conventional wisdom would suggest that the limit of the last (Late Devensian) ice sheet lay far to the west of the Inner Hebrides, so why should an idea exist that this ice limit may have been located closer to the Scottish mainland? The initial discussion of this topic was presented by Dawson (1982) with new data described in several later papers (Benn & Dawson 1987; Dawson et al. 1997; Dawson & Dawson 2001). The interpretation of the regional deglacial history is based on geomorphological and stratigraphical evidence not mentioned in Peacock (2008). For purposes of clarity the key arguments are summarized below and their resolution is central to any understanding of the deglacial history of Islay and surrounding areas.