Scottish late-glacial moraines: debris supply, genesis and significance
Abstract
A variety of moraine forms were deposited by glaciers during the
Loch Lomond Stadial. Study of such moraines and related landforms
provides a valuable source of data on patterns of landscape evolution
and climatic change. This thesis presents detailed case-studies of
moraines in geologically and topographically contrasting areas on the
Island of Skye, Scotland. Geomorphological mapping,
sedimentological analyses and mathematical modelling techniques
were employed to determine the principal controls on moraine
morphology, composition and distribution. Particular emphasis was
placed on the provenance, transport and deposition of debris, and
their spatial variation. The results were used to construct a summary
model of glacial landform evolution, which relates different
sediment-landform associations to spatial and temporal controls,
particularly basin lithology and structure, topography, position of
deposition and ice-margin activity.
The initial stage of deglaciation in the study area was marked by a
series of readvances and/or stillstands. During this stage, the
lower-lying glaciers were more sensitive to climatic amelioration
than the higher glaciers. The subsequent phase was characterised by
more rapid deglaciation. Evidence for one instance of late-stage in
situ glacier stagnation is described. The results indicate that
landforms hitherto grouped as 'hummocky -moraine' formed by a
variety of processes. Such moraines formed by (a) uneven deposition
of supraglacially and/or -subglacially-derived debris at active ice
margins, (b) deposition at the stagnant margins of otherwise active
glaciers, and (c) deposition during uninterrupted glacier retreat or
areal stagnation. Differentiation and analysis of so-called 'hummocky
moraine' enables glacier behaviour, during the Lateglacial to be
interpreted in great detail.
Type
Thesis, PhD Doctor of Philosophy
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