Brief description
A gravity core (GC09) was collected from a depth of 166m within the Capricorn Channel, southern Great Barrier Reef (GBR). Analysis of other parameters revealed the Last Glacial Maximum (LGM) sitting at a depth of ~60cm's into the core. For this reason two samples were collected for X-ray Diffraction (XRD) analysis, the first at a depth of 5cm (GC09-5) representing interglacial sediment, and the second from a depth of 60cm (GC09-60) representing glacial sediment. Both samples exhibited high Mg calcite and aragonite, compared with calcite, suggesting that the primary carbonate influx to the core is from the surrounding reef platform, rather than pelagic influences. There was also a 10% increase in non carbonate material during the glacial, and this was primarily made up of feldspars and quartz indicating a relative increase in terrestrial sediment during the LGM.Lineage
Maintenance and Update Frequency: notPlanned
Statement: For X-ray Diffraction (XRD analysis) samples were ground in an agate mortar with acetone or ethanol, then dried, and filled into side-packed sample holders. Powder diffraction data was collected at room temperature with a Siemens D501 diffractometer at the Department of Earth and Marine Science, The Australian National University. The diffractometer was equipped with a curved graphite monochromator, a scintillation detector, and CuK alpha radiation was used. Scans were recorded in one pass from 2 to 70 degrees 2-theta, using a step-width of 0.02 degrees and a scan speed of 1 degree per minute. The results were interpreted using the SIEMENS software package Diffracplus Eva (2000), and quantitative estimates were performed using the program Siroquant 2.5.
Statement: XRD analysis was undertaken for two samples within core GC09. The first, at 5cm depth represents interglacial sediment, while the deeper sample at 60cm (located at the LGM) represents glacial sediments. Clay data must be treated with caution since it has been suggested that clay minerals, transported to the coast by river suspended loads, undergo significant diagenesis within environments like mangroves. The percentages of sample components are not exact and the dataset also displays the % error of each component. Errors range from 0.2 - 2.4%.
Parameters: XRD run number, percentage of sample components (%), total percentage (%).
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 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.
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.
Issued: 25 06 2007
Data time period: 1997 to 1997
text: westlimit=151.5; southlimit=-24.5; eastlimit=153; northlimit=-23
text: uplimit=166; downlimit=166
Subjects
EARTH SCIENCE |
MARINE SEDIMENTS |
OCEAN/LAKE RECORDS |
OCEANS |
PALEOCLIMATE |
Sediment Composition |
Sediments |
amount_of_sample_components |
environment |
error |
User Contributed Tags
Login to tag this record with meaningful keywords to make it easier to discover
Other Information
(ANU_Bostock_GC09_5_data.xls)
global : abd6d050-22b1-11dc-8748-00188b4c0af8
Identifiers
- global : c09bb4c0-22bf-11dc-8748-00188b4c0af8
