Climate variability and ice-sheet dynamics during the last three glaciations

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doi: 10.1016/j.epsl.2014.09.004
Author(s): Obrochta, Stephen P.; Crowley, Thomas J.; Channell, James E. T.; Hodell, David A.; Baker, Paul A.; Seki, Arisa; Yokoyama, Yusuke
Author Affiliation(s): Primary:
University of Tokyo, Atmosphere and Ocean Research Institute, Tokyo, Japan
Braeheads Institute, United Kingdom
University of Florida, United States
University of Cambridge, United Kingdom
Duke University, United States
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.406, p.198-212. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. Includes appendices. 90 refs.; illus., incl. sketch maps
Summary: A composite North Atlantic record from DSDP Site 609 and IODP Site U1308 spans the past 300,000 years and shows that variability within the penultimate glaciation differed substantially from that of the surrounding two glaciations. Hematite-stained grains exhibit similar repetitive down-core variations within the Marine Isotope Stage (MIS) 8 and 4-2 intervals, but little cyclic variability within the MIS 6 section. There is also no petrologic evidence, in terms of detrital carbonate-rich (Heinrich) layers, for surging of the Laurentide Ice Sheet through the Hudson Strait during MIS 6. Rather, very high background concentration of iceberg-rafted debris (IRD) indicates near continuous glacial meltwater input that likely increased thermohaline disruption sensitivity to relatively weak forcing events, such as expanded sea ice over deepwater formation sites. Altered (sub)tropical precipitation patterns and Antarctic warming during high orbital precession and low 65°N summer insolation appear related to high abundance of Icelandic glass shards and southward sea ice expansion. Differing European and North American ice sheet configurations, perhaps aided by larger variations in eccentricity leading to cooler summers, may have contributed to the relative stability of the Laurentide Ice Sheet in the Hudson Strait region during MIS 6. Abstract Copyright (2014) Elsevier, B.V.
Year of Publication: 2014
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
Key Words: 24 Surficial Geology, Quaternary Geology; Antarctica; Atlantic Ocean; Cenozoic; Climate forcing; DSDP Site 609; Deep Sea Drilling Project; Detritus; Eccentricity; Expedition 303; Expeditions 303/306; Glaciation; Heinrich events; IODP Site U1308; IPOD; Ice; Ice rafting; Ice sheets; Insolation; Integrated Ocean Drilling Program; Laurentide ice sheet; Leg 94; MIS 6; MIS 8; Marine sediments; Meltwater; Mid-Atlantic Ridge; North Atlantic; North Atlantic Deep Water; Northeast Atlantic; Orbital forcing; Paleoclimatology; Pleistocene; Precession; Quaternary; Sea ice; Sediments; Thermohaline circulation
Coordinates: N495240 N495241 W0241417 W0241418
N495300 N495300 W0241400 W0241400
Record ID: 2015068991
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands