Iron oxide tracers of ice sheet extent and sediment provenan

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TitleIron oxide tracers of ice sheet extent and sediment provenance in the ANDRILL AND-1B drill core, Ross Sea, AntarcticaAbstractThe AND-1B drill core recovered a 13.57. million. year Miocene through Pleistocene record from beneath the McMurdo Ice Shelf in Antarctica (77.9^circS, 167.1^circE). Varying sedimentary facies in the 1285. m core indicate glacial-interglacial cyclicity with the proximity of ice at the site ranging from grounding of ice in 917. m of water to ice free marine conditions. Broader interpretation of climatic conditions of the wider Ross Sea Embayment is deduced from provenance studies. Here we present an analysis of the iron oxide assemblages in the AND-1B core and interpret their variability with respect to wider paleoclimatic conditions. The core is naturally divided into an upper and lower succession by an expanded 170. m thick volcanic interval between 590 and 760. m. Above 590. m the Plio-Pleistocene glacial cycles are diatom rich and below 760. m late Miocene glacial cycles are terrigenous. Electron microscopy and rock magnetic parameters confirm the subdivision with biogenic silica diluting the terrigenous input (fine pseudo-single domain and stable single domain titanomagnetite from the McMurdo Volcanic Group with a variety of textures and compositions) above 590. m. Below 760. m, the Miocene section consists of coarse-grained ilmenite and multidomain magnetite derived from Transantarctic Mountain lithologies. This may reflect ice flow patterns and the absence of McMurdo Volcanic Group volcanic centers or indicate that volcanic centers had not yet grown to a significant size. The combined rock magnetic and electron microscopy signatures of magnetic minerals serve as provenance tracers in both ice proximal and distal sedimentary units, aiding in the study of ice sheet extent and dynamics, and the identification of ice rafted debris sources and dispersal patterns in the Ross Sea sector of Antarctica. Copyright 2013 Elsevier B.V.AcknowledgementsWe thank the ANDRILL MIS Science Team, drillers, curators, Raytheon Polar Services staff, and the ANDRILL Science ManagementOffice for their efforts and assistance during the ANDRILL Program. This work was supported by a grant from the U.S. National Science Foundation via subcontract from the ANDRILL Management Office. We thank Luisa Bouhot for laboratory assistance, U.S. Polar Rock Repository curator Anne Grunow for providing guidance and samples, and Stan Jacobs for access to sediment samples from NBP07-02. The ANDRILL Program is a multinational collaboration between the Antarctic Programs of Germany, Italy, New Zealand, and the United States. Antarctica New Zealand is the project operator, and has developed the drilling system in collaboration with Alex Pyne at Victoria University of Wellington and Webster Drilling and Enterprises Ltd. Scientific studies are jointly supported by the U.S. National Science Foundation, NZ Foundation for Research Science and Technology, Royal Society of New Zealand Marsden Fund, the Italian Antarctic Research Programme (PNRA), the German Research Foundation (DFG, Project KU 683/8), and the Alfred-Wegener Institut Helmholtz-Zentrum fÃ¼r Polar- und Meeresforschung. Antarctica New Zealand supported the drilling team at Scott Base; Raytheon Polar Services supported the science team at McMurdo Station and the Crary Science and Engineering Laboratory. The ANDRILL Science Management Office at the University of Nebraska-Lincoln provided science planning and operational support. This manuscript was improved by the thoughtful comments provided by two anonymous reviewers and the GPC editorial staff.Funding DetailsKU 683/8, DFG, Deutsche Forschungsgemeinschaft

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1st AuthorBrachfeld, S.AuthorBrachfeld, S.Pinzon, J.Darley, J.Sagnotti, L.Kuhn, G.Florindo, F.Wilson, G.Ohneiser, C.Monien, D.Joseph, L.Year2013JournalGlobal and Planetary ChangeVolume110Pages420-433DOI10.1016/j.gloplacha.2013.09.015URLhttps://www.scopus.com/inward/recor.....dc45506f5564e1e521deab9faKeywordsAndrillAntarctic ice sheetsClimatic conditionsMagnetic parametersMcmurdo ice shelvesProvenance studiesRock magnetismSediment provenance, Core drillingElectron microscopesElectron microscopyGlacial geologyGlaciersIron oxidesLithologySedimentologyVolcanoes, Ice, cyclicityelectron microscopyfaciesglacial-interglacial cycleice free corridorice sheetice-rafted debrisiron oxidepaleoclimateprovenancetracer, AntarcticaEast AntarcticaMcMurdo Ice ShelfRoss SeaSouthern Ocean, Bacillariophyta, rank5Author KeywordsANDRILLAntarctic Ice SheetElectron microscopyRock magnetismSediment provenance

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TypeArticleCitationBrachfeld, S., Pinzon, J., Darley, J., Sagnotti, L., Kuhn, G., Florindo, F., Wilson, G., Ohneiser, C., Monien, D. and Joseph, L. (2013). Iron oxide tracers of ice sheet extent and sediment provenance in the ANDRILL AND-1B drill core, Ross Sea, Antarctica. Global and Planetary Change, 110:420-433 IdentifierBrachfeld2013Relevancerank5

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Wilson, G.