Geomorphology and sedimentology of the Caol Lairig valley, Scottish Highlands: evidence for local glacier margin advance and retreat during the Loch Lomond Stadial

Gareth Tye, Adrian Palmer

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Abstract

A sedimentological investigation of new sections of Loch Lomond Stadial (LLS) age deposits is presented from Caol Lairig valley, located adjacent to Glen Roy, Lochaber, Scottish Highlands. The ice lobes in Caol Lairig and Glen Roy blocked local fluvial drainage systems forming lakes that cut shorelines, the ‘Parallel Roads of Glen Roy’ (Agassiz, 1840; Jamieson, 1863, 1892). Within Caol Lairig sediment sequences of proximal, distal and deltaic glaciolacustrine sediments and a subglacial till are reported. The till was deposited during ice advance into the valley and the different glaciolacustrine facies formed in the gap between the head of Caol Lairig and the receding ice margin. When the sediments are related to the shoreline and glacial geomorphological evidence, phases of ice advance and ice retreat and the concomitant changes in lake levels are identified. Initially ice retreat in Glen Roy and Caol Lairig was synchronous but after the fall to 325 m the ice in Glen Roy retreated more quickly than in Caol Lairig. Differences in the ice thickness and the lake water depth in Glen Roy and Caol Lairig may have lead to preferential calving of the Glen Roy ice margin hastening ice retreat.
Original languageEnglish
Pages (from-to)67–82
Number of pages16
JournalProceedings of the Geologists' Association
Volume128
Issue number1
Early online date13 Dec 2016
DOIs
Publication statusPublished - Feb 2017

Keywords

  • Sedimentology Loch Lomond Readvance Glacier dynamics Caol Lairig Glen Roy

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