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The Last Scottish Ice Sheet

Ballantyne, Colin K.; Small, David

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Colin K. Ballantyne


The last Scottish Ice Sheet (SIS) expanded from a pre-existing ice cap after ∼35 ka. Highland ice dominated, with subsequent build-up of a Southern Uplands ice mass. The Outer Hebrides, Skye, Mull, the Cairngorms and Shetland supported persistent independent ice centres. Expansion was accompanied by ice-divide migration and switching flow directions. Ice nourished in Scotland reached the Atlantic Shelf break in some sectors but only mid-shelf in others, was confluent with the Fennoscandian Ice Sheet (FIS) in the North Sea Basin, extended into northern England, and fed the Irish Sea Ice Stream and a lobe that reached East Anglia. The timing of maximum extent was diachronous, from ∼30–27 ka on the Atlantic Shelf to ∼22–21 ka in Yorkshire. The SIS buried all mountains, but experienced periods of thickening alternating with drawdown driven by ice streams such as the Minch, the Hebrides and the Moray Firth Ice Streams. Submarine moraine banks indicate oscillating retreat and progressive decoupling of Highland ice from Orkney–Shetland ice. The pattern and timing of separation of the SIS and FIS in the North Sea Basin remain uncertain. Available evidence suggests that by ∼17 ka, much of the Sea of the Hebrides, the Outer Hebrides, Caithness and the coasts of E Scotland were deglaciated. By ∼16 ka, the Solway lowlands, Orkney and Shetland were deglaciated, the SIS and Irish Ice Sheet had separated, the ice margin lay along the western seaboard, nunataks had emerged in Wester Ross, the ice margin lay N of the Cairngorms and the sea had invaded the Tay and Forth estuaries. By ∼15 ka, most of the Southern Uplands, the Firth of Clyde, the Midland Valley and the upper Spey valley were deglaciated, and in NW Scotland ice was retreating from fjords and valleys. By the onset of rapid warming at ∼14.7 ka, much of the remnant SIS was confined within the limits of Younger Dryas glaciation. The SIS, therefore, lost most of its mass during the Dimlington Stade. It is uncertain whether fragments of the SIS persisted on high ground throughout the Lateglacial Interstade.


Ballantyne, C. K., & Small, D. (2018). The Last Scottish Ice Sheet. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 110(1-2), 93-131.

Journal Article Type Article
Online Publication Date May 15, 2018
Publication Date May 15, 2018
Deposit Date Jan 7, 2019
Publicly Available Date Jan 9, 2019
Journal Earth and Environmental Science Transactions of the Royal Society of Edinburgh
Print ISSN 1755-6910
Electronic ISSN 1755-6929
Publisher Cambridge University Press
Peer Reviewed Peer Reviewed
Volume 110
Issue 1-2
Pages 93-131
Related Public URLs


Accepted Journal Article (7.3 Mb)

Copyright Statement
This article has been published in a revised form in Earth and environmental science transactions of the Royal Society of Edinburgh This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © The Royal Society of Edinburgh 2018.

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