New Constraints on Late Pleistocene Sea Levels across Western Scotland with Implications for the Wester Ross Readvance

• Main Authors: Simms, Alexander R, Best, Louise, Shennan, Ian, Osleger, Dillon, Lisiecki, Lorraine, Sefton, Juliet, Lloyd, Jeremy, Lightowler, Amy
• Format: Conference Object
• Language: unknown
• Published: 2019
• Subjects: G Geography (General); GB Physical geography; GE Environmental Sciences; Greenland; Greenland ice cores; Ice Sheet
• Online Access: https://eprints.glos.ac.uk/14354/; http://iqua.ie/wp-content/uploads/2020/02/INQUA-2019-Abstract-book.pdf

Reconstructing the past behavior of ice sheets through the Late Pleistocene provides a means for understanding how ice sheets respond to climate change. Following the last glacial maximum, the British Ice Sheet retreated in response to warming and global sea-level rise. The retreat of the ice sheet over northwest Scotland is partly reflected in local records of sea-level change as well as moraines left behind within the landscape. We provide new constraints on the relative sea-level record of northwest Scotland based on two newly cored isolations basins. A record of magnetic susceptibility from one of these basins closely tracks climate changes recorded in the Greenland ice cores and is used to tune our age model from one of the basins. The new sea-level index points suggest sea level was 17.26+/-0.10 m at 14.9-15.8 ka within Glac Bhuidhe and 12.65+/-0.05 m at 15.7-16.1 ka with Loch Bad n h-Aclaise, both near the town of Gairloch in northwestern Scotland. Neither basin provides evidence for a “double-dip” in sea level during meltwater pulse 1-A as some models of glacial-isostatic adjustment predict for northwestern Scotland. As both basins lie within the limits of moraines associated with a regional readvance known locally as the Wester Ross Readvance, they constrain the age of the glacial event to greater than 15.8 ka. This age is within error of some rescaled cosmogenic ages and older than most previous models and point to a pre-Bølling Allerød age for the readvance, suggesting it may correlate to the Killard Point Readvance in Ireland and/or Heinrich Event 1. Furthermore, the basin stratigraphy records other regional climate events including the Younger Dryas and Bølling Allerød.