A palaeo-glaciological reconstruction of the last Irish Ice Sheet.

An inversion of the glacial geomorphological record provides an effective means to reconstruct
former ice sheets at ice sheet-scale. The last Irish Ice Sheet has a long history of investigation,
but its most basic properties are debated. Much previous research, based on an incremental
development of knowledge through field observation of glacigenic landforms and deposits, has
locally yielded high levels of detail but this detail is spatially fragmented across the former ice
sheet bed. The evidence-base for ice sheet reconstruction is therefore patchy and incomplete,
and its internal inconsistencies make an ice sheet reconstruction, via this approach, problematic.
This thesis explores new opportunities for palaeo-glaciological reconstruction offered by
remotely sensed data. Systematic glacial landform mapping has been conducted throughout
Ireland from a variety of satellite imagery and digital elevation models, and yields new Glacial
Maps for Ireland comprising >39,000 landforms. These landform maps are the building blocks
for a palaeo-glaciological reconstruction of the ice sheet. Adopting a 'flowset' approach, the full
population of landform data is summarised as discrete cartographic units - flowsets - and their
spatial, temporal and glaciodynamic information is extracted. The flowset record, integrated
with the wealth of evidence and dating constraints in the literature, stimulates a reconstruction
describing seven broad stages of ice sheet history. These provide a framework for the evolution
of the last Irish Ice Sheet.
Key elements of the reconstruction confirm and extend an early advance from a British ice
source, a maximum period likely dominated by large ice streams, fragmentation of the ice sheet
into separate ice bodies during retreat, and final decay in western mountain groups. The pattern
of ice sheet evolution is both asymmetric and asynchronous. A range of scales of ice sheet
behaviour are observed, from first-order, fundamental changes in ice sheet geometry (centres of
mass and ice flow structure) to more local-scale high-frequency fluctuations of ice flow
patterns. This new model acts as a framework for continued investigation of the evolution of the
Irish Ice Sheet, and the observed ice sheet behaviour demands further exploration of the
sensitivities and role of ice sheets in the wider ice - climate system.