Postglacial Relative Sea-Level Change on the Isle of Skye and Implications for Early Human Settlement

Lithic artefacts found in the modern intertidal and coastal environments of northern Skye indicate
Late Upper Palaeolithic human settlement in the area (Hardy et al., 2021) during the Loch Lomond
Stadial. Changes in relative sea level during this period enabled the migration of these peoples around
the ice margin on Skye, passing across land exposed by lower-than-present relative sea levels.
Artefacts associated with these settlers have been found in amongst raised beach deposits at a site in
northern Skye, some of which show evidence of reworking. Analysis is undertaken on sediment cores
retrieved from an isolation basin behind the raised beach to reconstruct changes in relative sea level
and palaeoenvironments, during the Postglacial and Holocene. The basal bedrock topography was
mapped through a ground-penetrating radar (GPR) survey and utilised to identify suitable sites for
sediment coring. The stratigraphy comprises lacustrine silts and clays at the base, followed by reedrich clastic sediments, which are overlain by sphagnum peat. Diatom analysis reveals a distinct
transition from freshwater to brackish conditions in the lacustrine deposits, dated to 8181 ± 144 years
before present. Two new sea level index points and a terrestrial limiting data point are extracted from
this isolation basin, the first such data from northern Skye. Bio-stratigraphic results reveal that this
isolation basin was inundated by the highest tides for a sustained period during the mid-Holocene.
Local patterns of relative sea level change reveal a strong possibility of a new submerged source for
these reworked lithics on the shallow foreshore at the site. Additionally, data from large-scale
reconstructions of relative sea levels and glacial ice extents of the Loch Lomond Stadial are used to
identify possible migratory routes of these Late Upper Palaeolithic settlers.