Revised magnetostratigraphic chronologies for New Harbour dr

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TitleRevised magnetostratigraphic chronologies for New Harbour drill cores, southern Victoria Land, AntarcticaAbstractThe Taylor Valley (DVDP-10, -11) and Ferrar Fiord (CIROS-2) drill cores offer a window into the evolution of southern Victoria Land glaciers and the Antarctic climate system during the late-Neogene. Here we present new magnetostratigraphic chronologies, which we use to correlate the drill core successions with onshore dry-valleys geomorphic records and offshore deep-ocean records. Magnetostratigraphies were constructed using stepwise AF and/or thermal demagnetisation of discrete specimens from the drill cores. Correlation of magnetostratigraphies with the magnetic polarity timescale was guided by biostratigraphic and radiometric constraints. We recognise five styles of sedimentation in the Taylor/Ferrar fiords, which we correlate with discrete climate phases. During the latest Miocene-early Pliocene, wet based glaciers filled the Taylor and Ferrar fiords with active sedimentation in the Taylor Fiord and erosion of basement rocks in the Ferrar Fiord. Glaciers retreated during the Pliocene warm period leaving open marine conditions and deep fiords (> 300. m) at a time when the Ross Sea was free of ice and sea surface temperatures around Antarctica were at least 5 ^circC warmer than today. We recognise the first significant cooling in DVDP-11 post 2.6. Ma by a shift to current winnowed sediments sourced from the Ross Sea rather than from East Antarctic glaciers. Post 1.7. Ma, lacustrine sediments were deposited behind ice-dammed lakes, which formed when West Antarctic ice expanded and grounded across the Ross Embayment and abutted the Transantarctic Mountains. Copyright 2011 Elsevier B.V.AcknowledgementsThis work was supported by the New Zealand Foundation for Research, Science and Technology as part of the New Zealand ANDRILL grant. We thank Fabio Florindo and Leonardo Sagnotti for helpful discussions and the technical support and Kat Lilly for help with EPMA analyses. We thank Matt Olney, Steven Petrushak, and Simon Harder. Holm Nielsen at the Antarctic Marine Geology Research Facility, Florida State University for assistance with sample collection. We are grateful for helpful discussions with Diane Winter and Richard Levy regarding biostratigraphic ages used in our correlations.

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TypeArticleCitationOhneiser, C. and Wilson, G. (2012) Revised magnetostratigraphic chronologies for New Harbour drill cores, southern Victoria Land, Antarctica. Global and Planetary Change, 82-83: 12-24 doi:10.1016/j.gloplacha.2011.11.007 IdentifierOhneiser2012Relevancerank3