Brief description
A gravity core (GC10) was collected from a depth of 335 mbsl within the Capricorn Channel, southern Great Barrier Reef (GBR). Isotopic values for 18O and 13C were obtained from Gs. ruber and correlated with the SPECMAP age-model. Radiocarbon dating of G. sacculifer was also undertaken at three sample depths, and then corrected and correlated with the curve. This yielded an age vs. depth profile from which it was possible to determine approximate sedimentation rates. The results place the Last Glacial Maximum (LGM) date at 130cm and highlights a peak in sedimentation rate during the penultimate glacial / interglacial transition. Down the core the sedimentation rates vary considerably from a high of 12 cm/kyr down to <1 cm/kyr. This is probably the result of a considerable change in the sediment flux related to the sea level fluctuations.Lineage
Maintenance and Update Frequency: notPlanned
Statement: Age-model constructed by correlating 18O data with the SPECMAP model of Martinson et al. Samples were dried in the oven before being re-soaked in distilled water. Samples then wet sieved through a series of four mesh sizes before the size fractions were transferred to drying trays. After drying foraminifera were picked from the large size fractions of >300 µm and >400µm. 10-15 white Gs. ruber were hand picked to give a total sample weight of 180-220µg for isotope analysis. The samples were washed in methanol and ultrasonicated for 30 secs to remove surface and internal particles. Samples were analysed at the Research School of Earth Science, Australian National University, using an automated individual carbonate reaction (Kiel) device coupled with a Finnigan MAT-251 mass spectrometer.
Radiocarbon dating was undertaken on ~300 individuals of G. sacculifer from >300µm size fraction. Samples were rinsed, ultrasonically cleaned, and then dried. Samples were then dissolved in 103% orthophosphoric acid and the CO2 collected under vacuum. The CO2 was converted to graphite by reacting with hydrogen over an iron catalyst at 600oC. The graphite, once formed, is transferred to small cathodes and run on the AMS.
Statement: Age estimates are provided for 5cm, 10cm, 15cm, 20cm and then every 10cm down the core to a depth of 450cm. These estimates were made primarily by correlating 18O values with the SPECMAP age-model. Values of 18O have a very small analytical error. Radiocarbon dating was undertaken on samples at 20cm, 70cm and 130cm depths. These values are provided, before being corrected and calibrated with the age curve.
Notes
CreditFunded by The Australian Research Council (ARC)
Credit
Funded by The Australian National University (ANU) Faculties Research Grant Scheme
Funded by The Australian National University (ANU) Faculties Research Grant Scheme
Purpose
To determine the sedimentological variations with sea-level over the last glacial/ interglacial cycle in the Capricorn Channel. Very little previous work has been undertaken within this area.
To determine the sedimentological variations with sea-level over the last glacial/ interglacial cycle in the Capricorn Channel. Very little previous work has been undertaken within this area.
Issued: 25 06 2007
Data time period: 1997 to 1997
text: westlimit=151.5; southlimit=-24.5; eastlimit=153; northlimit=-23
text: uplimit=335; downlimit=335
Subjects
51200000 |
EARTH SCIENCE |
Foraminifera |
Foraminiferans |
Foraminiferida |
MARINE SEDIMENTS |
OCEAN/LAKE RECORDS |
OCEANS |
PALEOCLIMATE |
Radiocarbon |
Sedimentation |
calibrated_age |
conventional_C14_age |
core_depth |
environment |
sedimentation_rate |
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Other Information
(ANU_Bostock_GC10_2_data.xls)
global : a1c4e840-237e-11dc-a78e-00188b4c0af8
Identifiers
- global : b7596070-2386-11dc-a78e-00188b4c0af8
