| Summary: | Maintenance and Update Frequency: notPlanned Statement: A sample from each depth was dried in the oven and ground up into a fine powder (~100mm) using a mortar and pestle. Approximately 1g of each sample was weighed accurately. 20ml of ~1mol/l HCl was added to the sample, and then heated and stirred until all the carbonate had reacted. Resulting solution was titrated with 0.5mol/l NaOH using the Metrohm Ion analysis 716 DMS Titrino series 6.0 to determine the CaCO3 %. Error range of 2% Statement: Values for CaCO3 % are recorded at 5cm, 10cm, 15cm, 20cm and then for every 10cm down the core until reaching a depth of 510cm. Percentage values for calcium carbonate have an error range of ± 2%. Parameters: Depth through core (cm), percentage of calcium carbonate (%). Credit Funded by The Australian Research Council (ARC) Credit Funded by The Australian National University (ANU) Faculties Research Grant Scheme Purpose To help determine changes in the carbonate mineralogy and terrestrial influx, which may provide some useful palaeoclimate information. Very little previous work has been undertaken within this area. A gravity core (GC12) was collected from a depth of 990.5 mbsl within the Capricorn Channel, southern Great Barrier Reef (GBR). The percentage of CaCO3 in samples collected from different depths were analysed, along with other parameters, to determine changes in carbonate mineralogy and terrestrial influx. Levels of CaCO3% exhibit an higher percentage of >60% during the middle of Marine Isotope Stage (MIS) 3, levels similar to those seen in MIS 1. Throughout MIS 2 and during the glacial termination the CaCO3% remains relatively constant at ~60%. CaCO3 drops to 50% prior to a possible Antarctic cold reversal (between 14 ka BP and 12 ka BP) at 80cm in the core, before recovering to the 65-70% in the Holocene again.
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