European Ice Sheet Complex Evolution During the Bølling–Allerød Interstadial (14.6–12.9 Ka)

During the Bølling–Allerød Interstadial, the extensive European Ice Sheet Complex (EISC) persisted over much of its domain, albeit split into independent ice sheets and remnant masses and in retreat. Here we give an overview of the Bølling–Allerød development of the EISC and its remnant bodies, and we introduce and synthesise the landscapes and characteristic landforms produced by these ice sheets, which are described in Chapters 29–33. The geomorphological record of the EISC gives an increasingly detailed picture of the pattern of ice sheet retreat during this period as well as powerful indicators of retreat behaviour, mechanisms and, qualitatively, rates of change, and we explore contrasts and commonalities in these elements between the marine and terrestrial ice sheet sectors. Conversely, chronological uncertainties are significant, particularly in the marine sectors but also around smaller remnant ice masses at the EISC periphery. These lend doubt to whether or not ice existed during the Bølling–Allerød in Britain and Ireland, and have profound implications for the role of the EISC in major sea level rise events and, consequently, the function of this ice sheet complex within the global climate system. Furthermore, the magnitude of retreat during the Bølling–Allerød is challenging to determine inboard of the well-defined Younger Dryas positions, and was likely variable across different sectors of the ice sheet complex. There is abundant evidence for substantial meltwater production during the Bølling–Allerød, and here we consider some of the wider ice–ocean–climate implications of meltwater discharge as well as how meltwater landform records from deglaciated ice sheet domains, including the EISC, continue to challenge and to stimulate important advances in understanding subglacial hydrology.