High-resolution record of foraminiferal response to late Quaternary sea-ice retreat in the Norwegian-Greenland Sea

Abstract

Dramatic oceanic changes during the transition from glacial to interglacial conditions had significant effects on pelagic and benthic environments in the Norwegian-Greenland Sea. Fossil marine biota in deep-sea sediments provide the means to reconstruct past oceanographic conditions and climatic fluctuations. Here we present the results of an investigation with high temporal resolution (±200 yr) of four sites distributed along a north-south transect across this high-latitude basin with the aim to decipher timing and regional relocation of water-mass boundaries. Results show that termination I in the Norwegian-Greenland Sea is characterized by a prominent maximum of benthic foraminiferal abundance, which progressively moved northward from the eastern North Atlantic Ocean to Fram Strait at a mean velocity of 0.77 km ṁ yr−1. Benthic foraminiferal accumulation rates during this abundance peak increase from south to north from 184 to 5863 specimens ṁ cm−2 ṁ k.y.−1. We interpret this abundance maximum to be a result of high organic carbon fluxes under a moving high productivity area, on the basis of the progression of climatic amelioration and retreat of sea-ice cover during the gradual deglaciation. The benthic foraminiferal record mirrors this time-transgressive belt directly.