We investigated surface- and deep-ocean variability in the subpolar North Atlantic from 500 to 1000 thousand years ago (ka) based on two Ocean Drilling Program (ODP) sites, Feni Drift Site 980 (55 degrees 29'N, 14 degrees 42'W) and Bjorn Drift Site 984 (61 degrees 25'N, 24 degrees 04'W). Benthic foraminiferal stable isotope data, planktic foraminiferal faunas, ice-rafted debris data, and faunally based sea-surface temperature estimates help test the hypothesis that oceanographic changes in the North Atlantic region were associated with the Mid-Pleistocene Revolution. Based on % Neogloboquadrina pachyderma (s) records from both sites, surface waters during interglacials and glacials were cooler in the mid-Pleistocene than during Marine Isotope Stages (MIS) 5 and 6. Furthermore, interglaciations at Bjorn Drift Site 984 were significantly cooler through the entire 500-1000 ka record. The position of the arctic front was traced by comparison of polar-water indicator % N. pachyderma (s) and sea-ice edge indicator % Globigerina quinqueloba. Our evidence suggests that the interglacial arctic front shifted from a position between the two sites to a position northwest of Bjorn Drift Site 984 after ca. 610 ka. Together with evidence for increased NADW formation during glacial initiations (starting at MIS 17/16), our findings are consistent with enhanced moisture transport to the subpolar North Atlantic during glacial initiations of the 100-kyr world.

West: -24.0457 East: -14.4208 North: 61.2532 South: 55.2906

Expedition: 162

Site: 162-980

Site: 162-984

Provider: SEDIS Publication Catalogue

Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=2003-031964 (c.f. for more detailed metadata)

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