Beryllium isotopes in sediments from Lake Maruwan Oike and Lake Skallen, East Antarctica, reveal substantial glacial discharge during the late Holocene

Abstract Constraining East Antarctic Ice Sheet (EAIS) evolution during the Holocene is important for exploring the forcing mechanisms behind ice sheet retreat and to constrain numerical ice sheet models that aid predictions of future sea-level rise. Beryllium (Be) isotope analysis of bedrock and marine sediments have offered unparalleled insight into Antarctic ice sheet history since the Pliocene, but much of EAIS remains poorly studied. Here, we report the reactive (authigenic) 10Be abundance, 9Be abundance and 10Be/9Be ratios of Antarctic lake sediments, for the first time, from Lake Maruwan Oike and Lake Skallen along Soya Coast of Lutzow-Holm Bay, East Antarctica. Beryllium isotope records reveal melting of local glaciers associated with higher subglacial erosion between ∼4.1 and ∼3.6 ka BP. Comparison to marine records from the Antarctic continental shelf suggests this was part of a circum-Antarctic phenomena that led to widespread glacial discharge from other sectors of the East and West Antarctic Ice Sheet. We suggest the incursion of relatively warm Circumpolar Deep Water (CDW) into Lutzow-Holm Bay during the Late Holocene led to frontal and basal melting of ice sheets along the Soya Coast, supporting the notion of Antarctic ice sheet instabilities as a contributor to global sea-level rise since the Mid Holocene.