Full description
Geoscience Australia carried out a marine survey on Lord Howe Island shelf (NSW) in 2008 (SS06-2008) to map seabed bathymetry and characterise benthic environments through co-located sampling of surface sediments and infauna, rock coring, observation of benthic habitats using underwater towed video, and measurement of ocean tides and wave-generated currents. Sub-bottom profile data was also collected to map sediment thickness and shelf stratigraphy. Data and samples were acquired using the National Facility Research Vessel Southern Surveyor. Bathymetric data from this survey was merged with other pre-existing bathymetric data (including LADS) to generate a grid covering 1034 sq km. As part of a separate Geoscience Australia survey in 2007 (TAN0713), an oceanographic mooring was deployed on the northern edge of Lord Howe Island shelf. The mooring was recovered during the 2008 survey following a 6 month deployment.Seabed sediment samples were collected by a Smith McIntyre grab at a total of 36 locations (see Brooke et al. 2010). The full sample set represents 16 sampling stations, with multiple (2 or 3) samples taken at 10 of these stations.
Lineage
Maintenance and Update Frequency: asNeeded
Statement: Sediment grabs typically recovered a sample up to 5 cm by 12 cm in area and 5 cm thick, from which a 50 - 100 g sub-sample was taken to a depth of ~2 cm. Sediment grabs typically recovered about 0.1 cubic metres of undisturbed sediment, from which a 250 - 500 g sub-sample was taken to a depth of ~5 cm. Sub-samples were described from visual inspection, noting grain size, sorting, composition and Munsell colour then stored in plastic bags and refrigerated. In the laboratory, samples were used for grain size analysis and measurement of carbonate content on separate splits. Grain size measurement was undertaken by wet sieving to determine mud (less than 63 microns), sand (63-2000 microns) and gravel (greater than2000 microns) fractions as percentage of dry weight. A separate sub-sample (~1g) was used for laser diffraction measurement of the mud and sand fractions using a Malvern Mastersizer 2000, with results expressed as percentage of the total particle volume based on an average of three measurements on each sample. Summary statistics include arithmetic mean, standard deviation, skewness and kurtosis. Carbonate content was measured on the bulk fraction and sand fraction by acid digestion and measurement of resultant pressure, following Muller and Gastner (1979). Sediment data for Lord Howe Island shelf are a first generation product derived from the physical samples. No transformation of the data has been undertaken.
Issued: 2011
text: westlimit=158.95; southlimit=-31.62; eastlimit=159.21; northlimit=-31.4
Subjects
AU-NSW |
Bathymetry Grid |
CERF |
Earth Sciences |
Geology |
Marine Data |
Marine Geoscience |
Published_External |
abiotic surrogates |
geoscientificInformation |
marine |
sedimentology |
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Other Information
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Identifiers
- URL : pid.geoscience.gov.au/dataset/ga/72041
- global : a529430e-2183-0f20-e044-00144fdd4fa6
