PP029-0015
Timing and Paleoceanographic Impacts of Deglaciation of the Arctic Island Channels between the Arctic Ocean and Baffin Bay during the Holocene

Friday, 11 December 2020
Poster
Anne E Jennings1, Nicole Brooks2, Robert Kelleher2, Shaoting Feng3, John T Andrews2, Alexandra Jahn4, Marchitto Thomas1, Julio Sepulveda5 and Benoit Lecavalier6, (1)Institute of Arctic and Alpine Research, Boulder, CO, United States, (2)University of Colorado, INSTAAR, Boulder, CO, United States, (3)University of Colorado, INSTAAR, Boulder, United States, (4)University of Colorado Boulder, Atmospheric and Oceanic Sciences and Institute of Arctic and Alpine Research (INSTAAR), Boulder, CO, United States, (5)University of Colorado at Boulder, Department of Geological Sciences and the Institute of Arctic and Alpine Research, Boulder, CO, United States, (6)Memorial University of Newfoundland, St John's, NL, Canada
Abstract:
Multi-proxy analyses of radiocarbon-dated sediment cores combined with modeling are used to determine the timing and consequences of early Holocene ice-sheet retreat from marine channels in the Canadian Arctic Archipelago (CAA) that connect the Arctic Ocean with Baffin Bay. High sediment accumulation rates associated with deglaciation and high productivity in the North Water (NOW) polynya provide expanded sediment records that capture the dynamic evolution of the region throughout the Holocene. The project applies nutrient tracers from ICPMS on planktic foraminifers, algal biomarkers, quantitative X-ray diffraction mineralogy, benthic and planktic foraminiferal assemblages, and biogenic silica abundances determined by FTIR analysis, climate modeling with the Community Earth System Model (CESM) and Glacial Isostatic Adjustment modeling to test the influence of the opening of the western freshwater route of the Arctic-Atlantic throughflow on freshwater outflow to the North Atlantic and its consequences for the AMOC, whether glacial isostatic uplift of the CAA channels has changed the composition of the Arctic outflow through time, with consequences for ocean acidification and the AMOC, and whether the NOW formed as a consequence of increased Arctic sea-ice in the middle to late Holocene. Twenty-one new radiocarbon dates including a paired comparison of planktic and benthic foraminifera provide core chronologies and suggest an early Holocene local ocean reservoir correction for benthic carbonate organisms of 600 14C years. The onset of the agglutinated faunal zone and an increase in biogenic silica begins <8.7 and >8.3 cal ka BP; it coincides with the opening of Nares Strait and increased marine productivity. A subsequent increase in FTIR biogenic silica/opal occurs within the agglutinated zone <5.8 and >5.4 cal ka BP. This transition potentially is associated with development of the NOW.

This research is funded by National Science Foundation OPP-1804504.

<< Previous Abstract | Next Abstract >>