Palynological evidence for a southward shift of the North Atlantic Current at ∼2.6 Ma during the intensification of late Cenozoic Northern Hemisphere glaciation

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doi: 10.1002/2013PA002543
Author(s): Hennissen, Jan A. I.; Head, Martin J.; de Schepper, Stijn; Groeneveld, Jeroen
Author Affiliation(s): Primary:
University of Toronto, Department of Earth Sciences, Toronto, ON, Canada
Other:
University of Bergen, Norway
Uni Research Climate, Norway
Volume Title: Paleoceanography
Source: Paleoceanography, 29(6), p.564-580. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 124 refs.; illus., incl. 1 table, sketch map
Summary: The position of the North Atlantic Current (NAC) during the intensification of Northern Hemisphere glaciation (iNHG) has been evaluated using dinoflagellate cyst assemblages and foraminiferal geochemistry from a ∼260 kyr interval straddling the base of the Quaternary System from two sites: eastern North Atlantic Deep Sea Drilling Project Site 610 in the path of the present NAC and central North Atlantic Integrated Ocean Drilling Program Site U1313 in the subtropical gyre. Stable isotope and foraminiferal Mg/Ca analyses confirm cooling near the marine isotope stage (MIS) G7-G6 transition (2.74 Ma). However, a continued dominance of the dinoflagellate cyst Operculodinium centrocarpum sensu Wall and Dale (1966) indicates an active NAC in the eastern North Atlantic for a further 140 kyr. At MIS 104 (∼2.60 Ma), a profound dinoflagellate cyst assemblage turnover indicates NAC shutdown in the eastern North Atlantic, implying elevated atmospheric pressure over the Arctic and a resulting shift in the westerlies that would have driven the NAC. These findings challenge recent suggestions that there was no significant southward shift of the NAC or the Arctic Front during iNHG, and reveal a fundamental climatic reorganization near the base of the Quaternary. Abstract Copyright (2014), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2014
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Alkaline earth metals; Anomalinidae; Atlantic Ocean; C-13/C-12; Calcium; Carbon; Cassidulinacea; Cenozoic; Cibicidoides; Cibicidoides wuellerstorfi; DSDP Site 610; Deep Sea Drilling Project; Dinoflagellata; Expedition 306; Expeditions 303/306; Foraminifera; Globigerina; Globigerina bulloides; Globigerinacea; Globigerinidae; IODP Site U1313; IPOD; Integrated Ocean Drilling Program; Invertebrata; Isotope ratios; Isotopes; Leg 94; Magnesium; Marine environment; Metals; Mg/Ca; Microfossils; Mid-Atlantic Ridge; Neogene; North Atlantic; North Atlantic Current; O-18/O-16; Oxygen; Paleo-oceanography; Paleoclimatology; Paleoenvironment; Paleosalinity; Paleotemperature; Palynomorphs; Pliocene; Protista; Reworking; Rockall Trough; Rotaliina; Sea-surface temperature; Stable isotopes; Tertiary; Transport; Upper Pliocene
Coordinates: N410000 N410000 W0325700 W0325700
N531318 N531329 W0185312 W0185342
Record ID: 2014067963
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom