Geomorphological mapping, exposure lithostratigraphic analysis,
borehole logging and particle size distribution analysis data combined
with ERT and GPR data allowed the lithological and sedimentological
characterisation of the subsurface. ERT data collected with
three different electrode spacings supported the lithological characterisation
of unconsolidated sediments and allowed estimating the
depth to bedrock. GPR proved invaluable at depicting the internal architecture
of low-loss materials such as esker gravel and glaciolacustrine
sediments. Using a range of antenna frequencies resulted in the
detection of the subsurface internal architecture at different scales.
The radar facies approach used for data interpretation allowed patterns
encountered in the radargrams to be related to sedimentological
properties of the subsurface. ERT and GPR data complemented
each other and together provided a broad understanding of the subsurface
geology. The integration of these techniques with field and
laboratory data permitted the geological characterisation of the site
and the reconstruction of the depositional environment. The data
presented suggest deposition of the recorded facies by an ice sheet
retreating westwards. Firstly, diamicton was deposited subglacially
over limestone bedrock. A continuous tunnel fill esker ridge (Geashill
Esker) was then deposited overlying the diamicton under subglacial
conditions infilling a subglacial meltwater channel running east. A
subaqueous fan, indicating a lake water table of over 72 m OD, was
deposited parallel to the continuous tunnel fill as a long beaded
esker ridge composed of silt, sand and gravel overlying the subglacial
diamicton. Glaciolacustrine silts and clays were subsequently deposited
on the lower ground between the esker ridge and the fan at a
later stage of deglaciation. Furthermore, peat developed during
post-glacial times in a lake covering parts of the study area and
extending north from the esker ridge, peat deposits in the study
area were subsequently cut-away by anthropogenic activity.