Surface and sub-surface multi-proxy reconstruction of mid to late Holocene palaeoceanographic changes in Disko Bugt, West Greenland
Surface and sub-surface multi-proxy reconstruction of mid to late Holocene palaeoceanographic changes in Disko Bugt, West Greenland
Previously Published Material: Poster presents and discusses results of a multi-proxy study in Disko Bugt area, West Greenland. Several data sets (benthic foraminifera: Perner et al. 2011 in QSR, 2013 in The Holocene; Lloyd et al. 2011 in Geology; diatoms of core 343310: Krawczyk et al. 2013 in QSR, dinos of core 343300: Ouellet-Bernier et al. 2014 in The Holocene) are published recently and new data (diatoms, alkenones) are presented.
Abstract ID#: 35010
English Abstract:
We present new surface water proxy records of meltwater production (alkenone derived), relative sea surface temperature (diatom, alkenones) and sea ice (diatoms) changes from the Disko Bugt area in central West Greenland. We combine these new surface water reconstructions with published proxy records (benthic foraminifera - bottom water proxy; dinocysts – surface water proxy), along with atmospheric temperature (Camp Century ice core). This multi-proxy approach allows us to reconstruct centennial scale mid to late Holocene palaeoenvironmental evolution of Disko Bugt in more detail than previously possible. Combining surface and bottom water proxies identifies the close coupling between ocean circulation (West Greenland Current conditions), the atmosphere and the Greenland Ice Sheet. Centennial to millennial scale changes in the wider North Atlantic region lead to variations in the West Greenland Current (WGC). During periods with a relatively warm WGC, the atmosphere in west Greenland warms and glaciers retreat producing significant meltwater flux to the west Greenland margin. In contrast, during periods of cold WGC the atmosphere cools and glaciers advance. This highlights the longer-term influence of ocean forcing on ice sheet behavior. We also identify links between palaeoceanographic evolution in the Disko Bugt region and the history of human occupation. Cooler oceanographic conditions at 3.5 ka BP support the view that the Saqqaq people left Disko Bugt due to deteriorating climatic conditions. The disappearance of the Dorset people is less clear, but our new data indicate that it may be linked to a significant increase in meltwater flux causing cold coastal conditions at c. 2 ka BP. The subsequent settlement of the Norse is clearly associated with climatic amelioration during the Medieval Climate Anomaly and their disappearance linked to harsher conditions at the beginning of the Little Ice Age.