| Summary: | Maintenance and Update Frequency: notPlanned Statement: Material was recovered using a Kullenberg core. The method used to produce diatom slides from the sediment sample is described in the 'methodology' document uploaded within this record. Statement: The core was sampled every 10cm from the sediment surface down to a depth of 260cm. The majority of samples were poorly preserved and showed high levels of dissolution making identification to species level often difficult. Parameters: Core depth (cm), diatom species, diatom subtotal and silica subtotal. Credit Mountain Mass Spectrometry Laboratory (Colorado) Credit Institute of Antarctic and Southern Ocean Studies (IASOS) Credit Institut Français pour la Recherche et Technologie Polaires (IFRTP) Credit Terres Australes et Antarctiques Françaises (TAAF) Credit Australian Postgraduate Research Award (APRA) Purpose To reconstruct the first sea-surface temperature and sea-ice record history of the Southern Ocean south of Australia. Core MD88-779 was taken during the 1988 French ASPARA IV cruise in the South East Indian Ocean aboard the Marion Dufresne. The core is 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. A total of 37 diatom species and taxa were observed in the core samples, comprising predominantly warm-water fauna. The majority of samples were poorly preserved and showed high levels of dissolution making identification to species level often difficult. Species with greatest abundances were those more heavily silicified (e.g. Fragilariopsis kerguelansis), and to a lesser extent the warm-water forms (e.g. Fragilariopsis doliolu). 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 ...
|
|---|