Holocene relative sea level changes in a glacio-isostatic area: New data from south-west Scotland, United Kingdom

This paper contributes to knowledge of Holocene relative sea level change along the mainland Ayrshire coast and offshore Isle of Bute, SW Scotland, UK, where few such studies have previously been undertaken. Morphological studies (mapping and altitude survey), together with stratigraphical and biostratigraphical studies (pollen and diatom analyses and radiocarbon dating) disclose evidence for mid and late Holocene relative sea level changes. The Main Postglacial and Blairdrummond displaced shorelines, previously identified widely in mainland Scotland, are dated in the area at c. 6800 calibrated years (c. 6000 14C years) and c. 4200 calibrated years (c. 3800 14C years) BP respectively. This information is compared with previously published information for Scotland against the classical theoretical model of relative sea level change in areas of glacio-isostasy. For the mid and late Holocene, in conformity with the model, a falling sequence of relative sea level changes near the centre of uplift is replaced by a rising sequence towards the periphery, in which later shorelines overlap earlier ones. In particular, the Blairdrummond Shoreline, which overlaps the earlier Main Postglacial Shoreline, is identified as the highest Holocene shoreline over much of the coastline of Scotland.