State-of-the-art in studies of glacial isostatic adjustment for the British Isles: a literature review

Abstract

Understanding the effects of glacial isostatic adjustment (GIA) of the British Isles is essential for the assessment of past and future sea-level trends. GIA has been extensively examined in the literature, employing different research methods and observational data types. Geological evidence from palaeo-shorelines and undisturbed sedimentary deposits has been used to reconstruct long-term relative sea-level change since the Last Glacial Maximum. This information derived from sea-level index points has been employed to inform empirical isobase models of the uplift in Scotland using trend surface and Gaussian trend surface analysis, as well as to calibrate more theory-driven GIA models that rely on Earth mantle rheology and ice sheet history. Furthermore, current short-term rates of GIA-induced crustal motion during the past few decades have been measured using different geodetic techniques, mainly continuous GPS (CGPS) and absolute gravimetry (AG). AG-measurements are generally employed to increase the accuracy of the CGPS estimates. Synthetic aperture radar interferometry (InSAR) looks promising as a relatively new technique to measure crustal uplift in the northern parts of Great Britain, where the GIA-induced vertical land deformation has its highest rate. This literature review provides an in-depth comparison and discussion of the development of these different research approaches.

Quaternary sea level change in Scotland

“…Modelling approaches to isostatic uplift in Scotland were recently reviewed by Stockamp et al . (2016).…”

“…These models have normally involved polynomial quadratic trend surfaces (e.g., Smith et al 2000, but recently, a new approach, employing Gaussian quadratic trend surfaces (e.g., Fretwell et al 2004;Smith et al 2006Smith et al , 2012, provides a better fit than polynomial trend surfaces and has the additional benefit of defining a zero level for the surfaces computed. Modelling approaches to isostatic uplift in Scotland were recently reviewed by Stockamp et al (2016).…”

Testing the mid-Holocene relative sea-level highstand hypothesis in North Wales, UK

“…For the regional BRADLEY models, it may also be a result of incorrect estimation of isostatic change for the Holocene, or, perhaps most likely, a composite of these effects. Attributing a cause to this mismatch is complicated by a general GIA modelling problem, that many possible variables in the Earth-model can provide similar predictions with equally good fit to the empirical data (Stockamp et al 2016). Despite the closer fit of the BRADLEY models to the geological data it is clear there is still need for further refinement of model parameters to successfully match this region's relative sealevel data with GIA model predictions, particularly for the Mid-to Late Holocene.…”

Advances in Quaternary studies and geomorphology in Scotland: implications for geoconservation

“…2012; Stockamp et al . 2016) that can be tested and refined against the detailed studies of RSL changes now available from Scotland and more widely across the British Isles (Shennan et al . 2006b, 2018; Smith et al .…”

“…The development of quantitative GIA models (Bradley et al 2011;Kuchar et al 2012;Stockamp et al 2016) that can be tested and refined against the detailed studies of RSL changes now available from Scotland and more widely across the British Isles (Shennan et al 2006b(Shennan et al , 2018Smith et al 2018) is enabling better understanding of the rheology of the upper mantle, glacio-isostatic adjustment, BIIS ice sheet extent, far-field deglacial chronology and the magnitude and timing of global meltwater discharge, the final deglaciation of the Laurentide ice sheet and melting of the Antarctic Ice Sheet after 7 ka BP (Shennan et al 2005(Shennan et al , 2006a(Shennan et al , 2018. Critically, however, more high-precision records are required from a range of sites, particularly in the N and W, to establish RSL variations during the last ca.2000 years to help inform projections of future changes (Smith et al 2018).…”