The influence of ice marginal setting on early Holocene retreat rates in central West Greenland

Ice sheet reconstructions from diverse ice margin settings, spanning multiple millennia, are needed to assess the reaction of the Greenland Ice Sheet (GrIS) to millennial-scale climatic forcing and to place historical records in a longer-term context. Here we present 18 new cosmogenic ¹⁰Be exposure ages and five new radiocarbon ages that constrain the early Holocene retreat of the GrIS in the Disko Bugt region in both a marine and a land-based setting. Results indicate similar rates of early Holocene retreat of ~40-50m a^-1 from transects in Torsukattak fjord (marine setting) and the Naternaq area (land-based setting). We compile seven previously published chronologies of deglaciation from West Greenland, which yield early Holocene retreat rates ranging from 10 to 65m a^-1, similar to those determined for our two study areas. This work demonstrates that when averaged on millennial timescales, retreat rates were remarkably similar along the western GrIS margin. Furthermore, the retreat rates calculated here demonstrate that terrestrial sectors of ice sheets can retreat at net rates comparable to their marine counterparts.