Data

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

Australian Ocean Data Network
Armand, Leanne ; De Deckker, Patrick ; Pichon, Jean-Jacques
Viewed: [[ro.stat.viewed]] Cited: [[ro.stat.cited]] Accessed: [[ro.stat.accessed]]
ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=https://catalogue.aodn.org.au:443/geonetwork/srv/api/records/5e15b270-5a86-11dc-bd3f-00188b4c0af8&rft.title=Oxygen-isotope records, age-model results and sedimentation rates of core MD88-779&rft.identifier=https://catalogue.aodn.org.au:443/geonetwork/srv/api/records/5e15b270-5a86-11dc-bd3f-00188b4c0af8&rft.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 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.Maintenance and Update Frequency: notPlannedStatement: Material was recovered using a Kullenberg core. The method used to produce diatom slides from sediment samples is described in the 'methodology' document uploaded with this record.Statement: Each core age-model must be considered provisional since additional independent tie-points to age have not been made, such as AMS 14C dating of the foraminifera in the surface sediments, nor was the oxygen isotopic data of the cores at high resolution. Parameters: Oxygen-isotope core depth (cm), delta 18O from benthic foraminifera (C. wuellerstorfi), tie points in SPECMAP age scale (ka), corresponding SPECMAP age scale (ka), linear sedimentation rate (cm/ka), diatom core depth (cm), Analyseries extrapolated age scale (ka) at 10cm intervals, core sample dry weights (gm), field of views counted, diatom subtotal, number of diatom frustules (x1000000)/gm dry weight.&rft.creator=Armand, Leanne &rft.creator=De Deckker, Patrick &rft.creator=Pichon, Jean-Jacques &rft.date=2007&rft.coverage=westlimit=146.50; southlimit=-48.00; eastlimit=147.00; northlimit=-47.50&rft.coverage=westlimit=146.50; southlimit=-48.00; eastlimit=147.00; northlimit=-47.50&rft.coverage=uplimit=2266.7; downlimit=2260&rft.coverage=uplimit=2266.7; downlimit=2260&rft_rights=Creative Commons Attribution 2.5 Australia License http://creativecommons.org/licenses/by/2.5/au/&rft_rights=The citation in a list of references is: citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data accessed at (add http link).&rft_rights=Users are kindly requested to contact the principal investigator for authorisation before utilising or reproducing any material. For access to the data, please contact the principal investigator.&rft_subject=climatologyMeteorologyAtmosphere&rft_subject=environment&rft_subject=FORAMINIFERS&rft_subject=EARTH SCIENCE&rft_subject=BIOLOGICAL CLASSIFICATION&rft_subject=PROTISTS&rft_subject=AMOEBOIDS&rft_subject=OXYGEN ISOTOPES&rft_subject=PALEOCLIMATE&rft_subject=OCEAN/LAKE RECORDS&rft_subject=SEDIMENTATION&rft_subject=OCEANS&rft_subject=MARINE SEDIMENTS&rft_subject=Age model&rft_subject=C. wuellerstorfi&rft_subject=51200000&rft.type=dataset&rft.language=English Access the data
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The citation in a list of references is: citation author name/s (year metadata published), metadata title. Citation author organisation/s. File identifier and Data accessed at (add http link).

Users are kindly requested to contact the principal investigator for authorisation before utilising or reproducing any material. For access to the data, please contact the principal investigator.

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Full 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 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.

Lineage

Maintenance and Update Frequency: notPlanned
Statement: Material was recovered using a Kullenberg core. The method used to produce diatom slides from sediment samples is described in the 'methodology' document uploaded with this record.
Statement: Each core age-model must be considered provisional since additional independent tie-points to age have not been made, such as AMS 14C dating of the foraminifera in the surface sediments, nor was the oxygen isotopic data of the cores at high resolution. Parameters: Oxygen-isotope core depth (cm), delta 18O from benthic foraminifera (C. wuellerstorfi), tie points in SPECMAP age scale (ka), corresponding SPECMAP age scale (ka), linear sedimentation rate (cm/ka), diatom core depth (cm), Analyseries extrapolated age scale (ka) at 10cm intervals, core sample dry weights (gm), field of views counted, diatom subtotal, number of diatom frustules (x1000000)/gm dry weight.

Notes

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.

Issued: 29 08 2007

Data time period: 1988 to 1988

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147,-47.5 147,-48 146.5,-48 146.5,-47.5 147,-47.5

146.75,-47.75

text: westlimit=146.50; southlimit=-48.00; eastlimit=147.00; northlimit=-47.50

text: uplimit=2266.7; downlimit=2260

Subjects
51200000 | AMOEBOIDS | Age model | BIOLOGICAL CLASSIFICATION | C. wuellerstorfi | EARTH SCIENCE | Foraminifers | MARINE SEDIMENTS | OCEAN/LAKE RECORDS | OCEANS | Oxygen Isotopes | PALEOCLIMATE | PROTISTS | Sedimentation | climatologyMeteorologyAtmosphere | environment |

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Other Information
Methodology - Diatom preparation from sediment samples (App 1-1.pdf)

url : https://catalogue.aodn.org.au:443/geonetwork/srv/api/records/5e15b270-5a86-11dc-bd3f-00188b4c0af8/attachments/App 1-1.pdf

Identifiers
  • global : 5e15b270-5a86-11dc-bd3f-00188b4c0af8