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Oxygen-isotope records, age-model results and sedimentation rates of core MD88-779

Created 25/06/2017

Updated 11/08/2023

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Core MD88-779 was taken during the 1988 French ASPARA IV cruise in the South East Indian Ocean aboard the Marion DuFresne. The core was situated on the South Tasman Rise (47º50.690S, 146º32.750E) at a depth of 2260m. Although the core recovered was 6.7m long, only the top 2.6m were studied as preliminary investigations had indicated that this section covered the last two glacial cycles.

Isotopic analysis was performed on tests of the benthic foraminifera Cibicidoides wuellerstorfi. The record contains two climatic cycles that reach into isotope-stage 7. The benthic isotope curve of core MD88-779, however, shows a melding of isotopic stages 3-5, which are difficult to separate with depth.

The age-model is derived through comparison with the benthic SPECMAP stack of Martinson et al. (1987). The core covers 200kyr over 260cm, and thus has a low sedimentation rate. It also shows a reduction of sedimentation from the Holocene rates to that of the last glacial (oxygen-isotope stage 2).

The complete loss of a diatom record at 170cm and 210/220cm in the core is extremely unusual. The diatom signal is interpreted as having been removed by increased water mass velocity, extreme post-depositional silica dissolution or decreased productivity. There is no sedimentological evidence from the core which provides further interpretation.

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Field Value
Title Oxygen-isotope records, age-model results and sedimentation rates of core MD88-779
Language English
Licence Creative Commons Attribution 2.5 Australia
Landing Page https://data.gov.au/data/dataset/a2dc00ad-4c81-4c7a-996c-8e17ce790d3c
Contact Point
Department of Biological Sciences, Macquarie University
leanne.armand@mq.edu.au
Reference Period 25/06/2017
Geospatial Coverage
Map data © OpenStreetMap contributors
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        147.0,
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      ],
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      ],
      [
        146.5,
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      ],
      [
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    ]
  ],
  "type": "Polygon"
}
Data Portal Data.gov.au