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Source of the climate signal recorded by magnetic susceptibility variations in Indian Ocean sediments.

Hounslow, Mark W. and Maher, Barbara A. (1999) Source of the climate signal recorded by magnetic susceptibility variations in Indian Ocean sediments. Journal of Geophysical Research: Solid Earth, 104. pp. 5047-5061. ISSN 2196-9356

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    Abstract

    The origins of magnetic susceptibility variations in deep-sea sediments from the Indian Ocean (ODP Leg 117) have been examined to identify the specific connections between climate shifts and sediment magnetic properties. In a previous study, the magnetic susceptibility variations in ODP Hole 722B were identified as an outstanding proxy paleoceanographic record, despite evidence of post-depositional loss of magnetic minerals through reductive diagenesis. This paradox is addressed by assessing the contributions of ferrimagnetic detrital iron oxides, bacterial magnetosomes, and paramagnetic detrital Fe-silicate minerals to the magnetic susceptibility signal. In addition to detailed magnetic analyses, mineralogical, morphological and grain size data have been obtained from representative magnetic extracts. For Hole 722B, magnetic responses to climate change result from: i) fluctuations in the volume magnetic susceptibility, which is primarily controlled by carbonate dilution; ii) a ferrimagnetic signal which is restricted to the upper 7 mbsf and which largely reflects source area aridity; and iii) a paramagnetic susceptibility record below 7 mbsf, which is coincident in frequency with variations in lithogenic grain size.

    Item Type: Article
    Journal or Publication Title: Journal of Geophysical Research: Solid Earth
    Additional Information: Copyright (1999) American Geophysical Union.
    Uncontrolled Keywords: Magnetic records ; climate change ; deep sea sediments ; magnetic susceptibility ; Indian Ocean
    Subjects: G Geography. Anthropology. Recreation > GC Oceanography
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 351
    Deposited By: Professor Barbara A Maher
    Deposited On: 19 Jan 2007
    Refereed?: Yes
    Published?: Published
    Last Modified: 17 Sep 2013 08:22
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/351

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