Towards improved empirical isobase models of Holocene land uplift for mainland Scotland, UK

Abstract

A new approach to modelling patterns of glacio-isostatic land uplift during the Holocene in mainland Scotland, UK, is described. The approach is based upon altitude measurements at the inner margin or locally highest point of raised estuarine surfaces dated by radiocarbon assay supported by microfossil analyses. 2,241 altitudes have been analysed by a technique new to studies of former sea-levels, Gaussian Trend Surface Analysis, and isobase models for four Holocene shorelines: the Holocene Storegga Slide tsunami shoreline, abandoned rapidly circa 7,900 sidereal years BP; the Main Postglacial shoreline, abandoned during circa 6,400-7,700 sidereal years BP; the Blairdrummond shoreline, abandoned during circa 4,500-5,800 sidereal years BP, and a speculative fourth shoreline, the Wigtown shoreline, abandoned during circa 1,520-3,700 sidereal years BP, are shown in a series of maps. The implications of the shoreline patterns for glaicio-isostasy in the area are discussed. It is maintained that the statistical technique used enables broad estimates to be made of near shore sea surface change.