Rapid Holocene relative sea-level changes in Gruinart, Isle of Islay, Scottish Inner Hebrides

Litho- and biostratigraphic analyses undertaken in the Gruinart estuary, central Islay, reveal a detailed sedimentary record of Holocene relative sea-level changes and high-energy flood events during the last 10 000 years. During the Lateglacial-Holocene transition relative sea level had fallen to below c. 0.5 m OD and remained at this depth until c. 8830 ¹⁴C years BP. Thus, the early-Holocene minimum sea level is here, relatively well constrained altitudinally. A sustained and largely uninterrupted rise in relative sea level took place after c. 8500 ¹⁴C years BP, reaching a maximum altitude of c. 4.5 m OD, and remained at an elevation of c. 4 m OD until c. 2000 ¹⁴C years BP. Both the recorded maximum altitude of the Main Holocene transgression and the late age of the relative marine regression are incompatible with published shoreline uplift isobase models for this area.