Palaeoclimate and sea-level inferences from Ringgåsvatnet, Nordaustlandet, Svalbard Archipelago.

<p>The overarching aim of the project is to contextualise glacier activity across a transect of the Svalbard Archipelago to reconstruct and infer the past climatic and atmosphere-ocean interaction during the Late Quaternary, thus enabling the determination of temperature and precipitation gradients across the archipelago as well as identifying shifts in the positioning and coalescing of the polar air and ocean masses. Palaeoclimates will be reconstructed along a highly sensitive transect across the Svalbard Archipelago ranging from the east at northern Nordaustlandet, northern Spitsbergen and Erdmannflya in southwest central Spitsbergen. This will be elucidated by the investigation of Quaternary geomorphology, sea-level histories, proxies, and geochrononologies from lacustrine sediment records and terrestrial surface exposure dating. The lake Ringg&#229;svatnet is situated above 80&#186;N on Nordaustlandet, northeast Svalbard Archipelago. Sediment cores were retrieved in 2017 and have undergone of analysis and interpretation of the glacial, sea-level and palaeoclimate story contained within. Ringg&#229;svatnet forms part of transect of cores that seek to elucidate the evolution of palaeoclimatic gradients across Svalbard during the Holocene. Ahlmannfonna resides within the main catchment of Ringg&#229;svatnet, and likely receiving meltwater from the northwest margin of Austfonna ice cap during deglaciation. The cores record the post-glacial emergence of Ringg&#229;svatnet and the surrounding terrain, with initial isolation of the basin dated to the Early Holocene based on AMS ¹⁴C radiocarbon dates on terrestrial macrofossils and foraminifera supported by other chronological approaches (²¹⁰Pb, PSV). Marine and lacustrine sedimentation in Ringg&#229;svatnet and its post-glacial emergence denote a clear shift in the climate during the Holocene. The core record contains a basal marine unit which transitions to a distinct phase of the Ringg&#229;svatnet basin becoming isolated rather abruptly over a short period. This then gives way to a lacustrine environment dominated by minerogenic input primarily of a glaciogenic origin with several phases / oscillations of glaciogenic sediment variability interpreted as glacial activity. There are multiple oxidized horizons throughout the lacustrine phase of the indicating periods of short but higher biogenic / organic productivity. There appears to be no distinct / extensive period of no glaciogenic input into Ringg&#229;svatnet during the Holocene, suggesting that Ahlmannfonna remained throughout and did not disappear, although it may have remained in a heavily reduced state during the Holocene Climatic Optimum / mid-Holocene.</p>