Brief description
Core MD88-787 was recovered during the French ASPARA IV cruise in 1988, aboard the Marion Dufresne. The core was located on the Tasman Fracture Zone of the Mid-Ocean Ridge, within the Polar Front Zone.Sediment samples were taken at 10cm intervals. Isotopic analysis was performed on tests of the planktonic foraminifera Neogloboquadrina pachyderma (200-250um), and revealed that the core covered two climatic cycles. The base of the core was found to represent the end of isotope-stage 7, as was suggested by the last abundant appearance datum (LAAD) of H. karstenii.
The core contained 195kyr of sedimentation within its 1030cm length. The results also indicate that the Holocene period has the highest rates of sedimentation observed through time. Further variations (excluding isotope-stage 1) appear to indicate that a reduction of the sedimentation rate occurred during the interglacial periods, in contrast to that of the glacials.
Lineage
Maintenance and Update Frequency: notPlannedThe method used to produce diatom slides from sediment samples is described in the 'methodology' document uploaded with this record.
The core age model must be considered provisional since additional independent tie-points to age have not been made for the cores, such as AMS 14C dating of the foraminifera in the surface sediments, nor was the oxygen isotopic data of the cores at high resolution.
There is room for error in the positioning of the last abundant appearance datum of H. karstenii at the base of the core, as the core ends just where the signal begins to increase.
Parameters: Core depth (cm), delta 18O (using N.pachyderma), tie-points in SPECMAP age scale (ka), correspoding SPECMAP age scale (ka), linear sedimentation rate (cm/ka), Analyseries extrapolated age scale (ka) at 10cm interval, core sample dry weights (gm), field of views counted, diatom subtotal count, number of diatom frustules (x1000000)/gm dry weight, diatom transfer function factor 1 loading, diatom transfer function factor 2 loading, diatom transfer function factor 3 loading, diatom transfer function factor 4 loading, diatom transfer function factor 5 loading, diatom transfer function factor 6 loading.
Notes
CreditCentre des Faibles Radioactivities mixte CNRS CEA (France)
Institute of Antarctic and Southern Ocean Studies (IASOS)
Institut Français pour la Recherche et Technologie Polaires (IFRTP)
Terres Australes et Antarctiques Françaises (TAAF)
Australian Postgraduate Research Award (APRA)
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=145; southlimit=-56.50; eastlimit=145.5; northlimit=-56.00
text: uplimit=3030.4; downlimit=3020
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Methodology - Diatom preparation from sediment samples (App_1-1.pdf)
- global : f1924040-5a8b-11dc-bd3f-00188b4c0af8