The West Corrib moraine system as evidence for a brief glacial readvance in Ireland during overall Heinrich Stadial 1 deglaciation

Abstract An extensive system of end moraines in the western Lough Corrib basin, Ireland, which we term the West Corrib moraine system (WCMS), represents a brief period of ice-marginal stability or readvance that interrupted the overall pattern of deglaciation during Heinrich Stadial 1 (HS1: ca. 18.2–14.7 ka). In this study, we applied geomorphic mapping, sedimentology, and cosmogenic 10 Be surface-exposure dating to constrain the age of the WCMS and reconstruct local ice-flow patterns at that time. Coupled with the existing deglacial record for this region, our new data reveal that (1) the WCMS was deposited approximately 16.5 ka by ice flowing east out of Connemara and (2) despite the topographic prominence and lateral continuity of the moraines, the glacial event represented by the WCMS was short-lived in nature relative to the ca. 3 ka duration of HS1. We propose that the WCMS reflects a brief reversal of stadial deglaciation in Ireland and highlight temporal similarities with well-dated mid-HS1 advances elsewhere in maritime Europe and beyond.