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

Publication ,  Journal Article
Obrochta, SP; Crowley, TJ; Channell, JET; Hodell, DA; Baker, PA; Seki, A; Yokoyama, Y
Published in: Earth and Planetary Science Letters
November 5, 2014

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.

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Published In

Earth and Planetary Science Letters

DOI

ISSN

0012-821X

Publication Date

November 5, 2014

Volume

406

Start / End Page

198 / 212

Related Subject Headings

  • Geochemistry & Geophysics
  • 51 Physical sciences
  • 37 Earth sciences
  • 04 Earth Sciences
  • 02 Physical Sciences
 

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Obrochta, S. P., Crowley, T. J., Channell, J. E. T., Hodell, D. A., Baker, P. A., Seki, A., & Yokoyama, Y. (2014). Climate variability and ice-sheet dynamics during the last three glaciations. Earth and Planetary Science Letters, 406, 198–212. https://doi.org/10.1016/j.epsl.2014.09.004
Obrochta, S. P., T. J. Crowley, J. E. T. Channell, D. A. Hodell, P. A. Baker, A. Seki, and Y. Yokoyama. “Climate variability and ice-sheet dynamics during the last three glaciations.” Earth and Planetary Science Letters 406 (November 5, 2014): 198–212. https://doi.org/10.1016/j.epsl.2014.09.004.
Obrochta SP, Crowley TJ, Channell JET, Hodell DA, Baker PA, Seki A, et al. Climate variability and ice-sheet dynamics during the last three glaciations. Earth and Planetary Science Letters. 2014 Nov 5;406:198–212.
Obrochta, S. P., et al. “Climate variability and ice-sheet dynamics during the last three glaciations.” Earth and Planetary Science Letters, vol. 406, Nov. 2014, pp. 198–212. Scopus, doi:10.1016/j.epsl.2014.09.004.
Obrochta SP, Crowley TJ, Channell JET, Hodell DA, Baker PA, Seki A, Yokoyama Y. Climate variability and ice-sheet dynamics during the last three glaciations. Earth and Planetary Science Letters. 2014 Nov 5;406:198–212.
Journal cover image

Published In

Earth and Planetary Science Letters

DOI

ISSN

0012-821X

Publication Date

November 5, 2014

Volume

406

Start / End Page

198 / 212

Related Subject Headings

  • Geochemistry & Geophysics
  • 51 Physical sciences
  • 37 Earth sciences
  • 04 Earth Sciences
  • 02 Physical Sciences