Planktic Foraminifera Record Early Holocene 14C Reservoir Ages in Arctic Gateway

• Main Authors: Werner, Kirstin, Sarnthein, Michael
• Format: Conference Object
• Language: unknown
• Published: 2016
• Subjects: Arctic; Arctic Ocean; Barents Sea; Foraminifera*; Fram Strait; Neogloboquadrina pachyderma; Nordic Seas; Spitsbergen
• Online Access: https://epic.awi.de/id/eprint/47805/; https://hdl.handle.net/10013/epic.59ed5bdf-5fe8-4e87-bb8d-5549d40a7a1f

In three Holocene high-resolution sediment cores from the Nordic Seas, the Barents Sea continental margin and eastern Fram Strait, we established narrow-spaced 14C records of various planktic foraminifera species to reconstruct local variations in the reservoir age of surface and subsurface waters. In the two northern cores Neogloboquadrina pachyderma (sin.) (Nps) shows a distinct Early Holocene 14C plateau at 9.3 to 9.1 14C ka, that we tuned to an atmospheric 14C plateau near 9.0 to 8.7 14C ka (IntCal 2013) that extends from 10.2 to 9.6 calendar ka. The outlined difference in (average) 14C age suggests a reservoir age of ∼400 years for the subsurface dweller Nps. Different planktic foraminifers that inhabit different water masses document different reservoir ages. In contrast to Nps the near-surface dweller N. incompta reveals an average reservoir age of 150 years, however, a further near-surface dweller, Turborotalita quinqueloba, a local Early Holocene reservoir age of up to 720 years at the Barents Sea continental margin. The latter age may indicate a local admixture of old and less saline Arctic surface waters from the East Spitsbergen Current. The Early Holocene 14C plateau forms a robust basis for a better correlation of paleoceanographic signals in all three sediment cores. For example, the onset of a maximum in T. quinqueloba that marks the onset of the Early Holocene Thermal Maximum in the Arctic Gateway is now defined near 10.5 cal ka, an event that possibly reflects an enhanced advection of Atlantic surface waters up to the Arctic Ocean.