Threshold behavior of a marine-based sector of the East Antarctic ice sheet in response to early Pliocene ocean warming

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doi: 10.1002/2014PA002704
Author(s): Hansen, Melissa A.; Passchier, Sandra; Khim, Boo-Keun; Song, Buhan; Williams, Trevor
Author Affiliation(s): Primary:
Montclair State University, Department of Earth and Environmental Studies, Montclair, NJ, United States
Pusan National University, South Korea
Lamont Doherty Earth Observatory, United States
Volume Title: Paleoceanography
Source: Paleoceanography, 30(6), p.789-801. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 69 refs.; illus., incl. strat. col., 2 tables, sketch map
Summary: We investigate the stability of the East Antarctic Ice Sheet (EAIS) on the Wilkes Land continental margin, Antarctica, utilizing a high-resolution record of ice-rafted debris (IRD) mass accumulation rates (MAR) from Integrated Ocean Drilling Program Site U1359. The relationship between orbital variations in the IRD record and climate drivers was evaluated to capture changes in the dynamics of a marine-based ice sheet in response to early Pliocene warming. Three IRD MAR excursions were observed and confirmed via scanning electron microscope microtextural analysis of sand grains. Time series analysis of the IRD MAR reveals obliquity-paced expansions of the ice sheet to the outer shelf prior to ∼4.6 Ma. A decline in the obliquity and a transition into a dominant precession response of IRD MAR occur at ∼4.6 Ma along with a decline in the amplitude of IRD MAR maxima to low background levels between ∼4.0 and ∼3.5 Ma. We speculate that as sea surface temperatures began to peak above 3°C during the early Pliocene climatic optimum, the ice shelves thinned, leading to a greater susceptibility to precession-forced summer insolation and the onset of persistent retreat of a marine-based portion of the EAIS. Abstract Copyright (2015), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Antarctic ice sheet; Antarctica; Biogenic processes; Calving; Cenozoic; Climate forcing; Debris; East Antarctic ice sheet; Electron microscopy data; Expedition 318; Framework silicates; Grain size; IODP Site U1359; Ice rafting; Icebergs; Integrated Ocean Drilling Program; Lithostratigraphy; Lower Pliocene; Marine environment; Marine sedimentation; Marine sediments; Neogene; Opal; Paleoclimatology; Paleoenvironment; Paleotemperature; Pliocene; Quartz; SEM data; Sea-surface temperature; Sedimentation; Sediments; Silica minerals; Silicates; Southern Ocean; Statistical analysis; Tertiary; Textures; Time series analysis; Wilkes Land
Coordinates: S645415 S645415 E1435738 E1435738
Record ID: 2015088750
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom