New Schmidt hammer exposure‐age dating calibrations for the Last Glacial Termination in NW Scotland: Development and application to undated Torridon Group sandstone surfaces in Wester Ross

Abstract

ABSTRACT An understanding of the terrestrial extent, retreat dynamics and climate–glacier coupling of ice masses during the Last Glacial Termination (LGT, ~18–11 ka) is often limited by a fragmentary geomorphological record and is dependent on precise, accurate and robust dating frameworks. For the first time, we successfully apply Schmidt hammer exposure‐age dating (SHD) to Torridonian sandstone surfaces (Applecross Formation) at 31 sites in NW Scotland. Field results from a 2000 km 2 area of Wester Ross demonstrate that application of the Schmidt hammer can detect statistically significant differences in R (rebound)‐values between surfaces exposed since the Wester Ross Readvance (~15.3 ± 0.7 ka) and the Loch Lomond Readvance (~12.9–11.7 ka). Based on 48 existing 10 Be ages from 18 landforms, we generate calibration equations for the LGT period for two 10 Be production rates, which are used to estimate SHD ages for nine previously undated landforms. Our findings are broadly consistent with current theory and field evidence, allow regional ice‐cover reconstructions to be tested and support the view that on selected lithologies and with rigorous adherence to, and careful consideration of field procedure and the wider evidence, SHD can represent a valuable, cost‐effective and reliable tool for obtaining large numerical dating samples for landforms in formerly glaciated terrain.