14. Data Report: The Magnetic Mineral Assemblage of Hemipelagic Drifts, ODP Site 10961

Stefanie A. Brachfeld,2 Y. Guyodo,3 and G.D. Acton4

INTRODUCTION

During Ocean Drilling Program (ODP) Leg 178, we drilled three sites on sediment drifts deposited on the continental rise on the western margin of the Antarctic Peninsula. These hemipelagic drifts were targeted for their potential to preserve a continuous record of the behavior of the West Antarctic Ice Sheet over the last 10 m.y. It has been proposed that drift development is linked to advances and retreats of the Antarctic continental ice sheet (Pudsey and Camerlenghi, 1998, and references therein; Barker, Camerlenghi, Acton, et al., 1999). However, the sediment is characterized by a very low carbonate content, with foraminifers restricted to very narrow intervals. This lack of carbonate precludes the construction of a 18O or CaCO3 stratigraphy, depriving these sites of an important chronologic tool and global ice volume proxy.

As an alternative, we have compiled a rock-magnetic data set. Rock-magnetic investigations serve several purposes:

  1. Continuous records of variations in the intensity of the geomagnetic field have been demonstrated to be powerful correlation and dating tools for the past 800 k.y. (Guyodo and Valet, 1996, 1999; Laj et al., 2000). The use of geomagnetic field paleointensity as a dating tool at this site requires the removal of climatic influences on the recording assemblage. Toward that end, rock-magnetic investigations have been carried out to assess the "uniformity" of the magnetic mineral assemblage (see Tauxe, 1993).
  2. Rock-magnetic parameters contain information regarding the source material and processes controlling the erosion, transport, and deposition of the sediment. Therefore, rock-magnetic parameters can be a valuable tool for both chronology and paleoclimate applications.

    1Brachfeld, S.A., Guyodo, Y., and Acton, G.D., 2001. Data report: The magnetic mineral assemblage of hemipelagic drifts, ODP Site 1096. In Barker, P.F., Camerlenghi, A., Acton, G.D., and Ramsay, A.T.S. (Eds.), Proc. ODP, Sci. Results, 178 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/178_SR/chap_14/chap_14.htm>. [Cited YYYY-MM-DD]

    2Byrd Polar Research Center, Ohio State University, 108 Scott Hall, 1090 Carmack Road, Columbus OH 43210, USA. brachfeld.2@osu.edu

    3Department of Geological Sciences, University of Florida, 241 Williamson Hall, PO Box 112120, Gainesville FL 32611-2120, USA.

    4Ocean Drilling Program, Texas A&M University, 1000 Discovery Drive, College Station TX 77845-9547, USA.

    Initial receipt: 26 January 2001
    Acceptance: 23 May 2001
    Web publication: 9 August 2001
    Ms 178SR-233

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