Subpolar North Atlantic surface and deep ocean circulation during the mid Pleistocene revolution

Author(s): Wright, Amy K.
Source: 163p. Institution: University of South Florida, , FL, United States
Note: In English. 85 refs. Master's thesis
Summary: 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°29'N, 14°42'W) and Bjorn Drift Site 984 (61°25'N, 24°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.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Atlantic Ocean; Benthic taxa; Bjorn Drift; Cenozoic; Feni Drift; Foraminifera; Globigerina; Globigerina quinqueloba; Globigerinacea; Globigerinidae; Holocene; Invertebrata; Leg 162; Marine sediments; Microfossils; Middle Pleistocene; Neogloboquadrina; Neogloboquadrina pachyderma; North Atlantic; ODP Site 980; ODP Site 984; Ocean Drilling Program; Paleo-oceanography; Paleocirculation; Paleoclimatology; Pleistocene; Protista; Quaternary; Rotaliina; Sediments; Subarctic regions; Upper Holocene
Coordinates: N552906 N552906 W0144208 W0144208
N612532 N612532 W0240457 W0240457
Record ID: 2003031964
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