Welsh Ice Sheet

A Glacial Geological Inversion Model of the Welsh Ice Sheet

Krister Jansson, Glasser, Neil

The aim of this project is to use the glacial geological and geomorphological landform record to constrain a model of the growth and decay of the last ice sheet that covered Wales. Glacial geological inversion models are now an established tool in reconstructions of the configuration and large-scale flow patterns of the Quaternary ice sheets, as undertaken by Kleman at Stockholm University. At a more local scale, it has been possible to identify glaciation event types (large-scale geomorphological units, each representing a specific set of erosional agents and formative conditions during the Quaternary Period) and to relate these to former subglacial thermal conditions.

Palaeogeographical reconstruction of a palaeo-ice stream that existed during the Late Devensian in the Conwy Valley, North Wales.
Palaeogeographical reconstruction of a palaeo-ice stream that existed during the Late Devensian in the Conwy Valley, North Wales.

In this project, we will use the spatial distribution of diagnostic landforms and sediments to gain insight into the dynamics and subglacial thermal regimes of the last ice sheet that covered Wales, paying particular attention to the mountainous regions that acted as source areas for the ice sheet. The project will involve synthesising large amounts of spatial data from a variety of published sources, interpretation of vertical aerial photographs and remote sensing images, fieldwork ground-truthing and data processing in a multi-layered GIS environment. Overall, this research will increase our understanding of glacial/climatic interactions and landscape evolution in Wales during the Quaternary Period.

SPOT satellite image, covering the Carrog area, North Wales. The image shows glacial lineations indicating ice flow towards northeast, forming part of the Bala Ice Stream.
SPOT satellite image, covering the Carrog area, North Wales. The image shows glacial lineations indicating ice flow towards northeast, forming part of the Bala Ice Stream.

This work has significance at all scales from local to global. It is relevant to Quaternary geology because geomorphology provides a framework for the interpretation of stratigraphical (point) data during ice-sheet growth and decay. It is relevant to numerical glaciological modelling because landforms are the most spatially-continuous record left by former ice sheets, and thus provide verification of numerical models. This research is also relevant to palaeoclimate research since knowledge about the temporal evolution of palaeo-ice sheet topography is essential for successful global circulation modelling. This work will also provide a framework that can be applied to other glaciated landscapes globally in studies of landscape evolution.