Brief description
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 silica dissolution or decreased productivity. There is no sedimentological evidence from the core which provides further interpretation.
The diatom recovery from this core is considerably low when compared to samples from the Southern Ocean.
Lineage
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.
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.
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.
Notes
CreditMountain Mass Spectrometry Laboratory (Colorado)
Credit
Institute of Antarctic and Southern Ocean Studies (IASOS)
Institute of Antarctic and Southern Ocean Studies (IASOS)
Credit
Institut Français pour la Recherche et Technologie Polaires (IFRTP)
Institut Français pour la Recherche et Technologie Polaires (IFRTP)
Credit
Terres Australes et Antarctiques Françaises (TAAF)
Terres Australes et Antarctiques Françaises (TAAF)
Credit
Australian Postgraduate Research Award (APRA)
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.
To reconstruct the first sea-surface temperature and sea-ice record history of the Southern Ocean south of Australia.
Issued: 29 08 2007
Data time period: 1988 to 1988
text: westlimit=130; southlimit=-48.00; eastlimit=155; northlimit=-35.00
text: uplimit=2266.7; downlimit=2260
Subjects
53001900 |
53120000 |
53150900 |
Azpeitia tabularis |
BIOLOGICAL CLASSIFICATION |
Diatoms |
EARTH SCIENCE |
Fragilariopsis doliolus |
Hemidiscus cuneiformis |
MICROALGAE |
PLANTS |
Roperia tesselata |
Thalassionema nitzschioides |
Thalassiosira lineata |
core_depth |
taxonomic_group_count |
taxonomic_name |
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Other Information
Methodology - Preparation of diatom slides from sediment samples (App 1-1.pdf)
Core MD88-779: Diatom raw counts (App 6-5 779.pdf)
Identifiers
- global : c091c950-5a9c-11dc-bd3f-00188b4c0af8
