Extent, style and timing of former glaciation in the Gaick, Central Grampians, Scotland, and implications for palaeoclimate
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The well-preserved record of glacial sediment-landform assemblages in Scotland provides an
excellent opportunity to reconstruct the extent and style of former glaciation. Despite a concerted
research effort, there remain areas where glacial events are poorly constrained. This is exemplified
by the Gaick, a dissected plateau in the Central Grampians, which has proven to be an enigmatic
and controversial area. Previously-proposed models fail to adequately explain glacial events in
the area, partly due to a paucity of detailed geomorphological, chronological and sedimentological
investigations.
This thesis presents the results of systematic studies of the sediment-landform record in the Gaick.
These investigations, combined with the application of morphostratigraphic principles, have
elucidated sediment-landform signatures indicative of multiple glacier fluctuations, specifically
(i) interactions of local and regional ice lobes following unzipping during ice sheet deglaciation,
(ii) a major stillstand of an extensive pre-Younger Dryas plateau icefield, and (iii) spatiallyrestricted
plateau icefield glaciation during the Younger Dryas. The sediment-landform record
also suggests a two-phased Younger Dryas advance, as has been found elsewhere in Scotland.
The sediment-landform evidence was used to produce palaeoglaciological reconstructions for the
three glacial phases. The clarity and completeness of the geomorphological record relating to the
Younger Dryas, combined with ice surface profile modelling, allowed the three-dimensional
reconstruction of a ~42 km2 plateau icefield. This reconstruction yielded an equilibrium line
altitude value of 751 ± 46 m, which was used to derive a sea-level equivalent precipitation
estimate of 826 ± 331 mm a-1. Taken together with glacier-derived precipitation estimates from
across Scotland, this indicates a strong west–east precipitation gradient during the Younger Dryas.
This thesis arrives at a more nuanced understanding of former glaciation in the Gaick, resolving
discrepancies with previous conceptual models. In particular, this thesis demonstrates that the
Gaick was an important ice dispersal centre throughout the Last Glacial-Interglacial Transition.
Authors
Chandler, Benjamin Marc PeterCollections
- Theses [4206]