Physical Properties and Bulk Chemical Composition of Continental Shelf and Slope Sediments of Australia

Updated: 2026-07-21

A number of physical properties (water content, porosity, wet and dry bulk densities, andgrain size) and the bulk chemical composition (percent calcium carbonate) of several corescollected from the Australian continental shelf and slope have been determined. Thecontinental shelf sediments were collected from water depths <200m in the Torquay Sub-basin and Vulcan Graben. Continental slope sediments were collected from water depthsof between 500 m and >4000 m offshore Evans Head (NSW), the Exmouth Plateau, thePerth Basin and the Ceduna Terrace in The Great Australian Bight. Trends between physical properties and the bulk chemical composition have beencompared and contrasted for continental shelf and slope sediments. Increasing carbonatecontent for sediments from the continental slope are associated with increasing wet bulkdensities. A second order polynomial fit to the data was similar to that found for deep-sea,southeast Pacific cores examined by Lyle and Dymond (1969). In contrast, the continentalshelf sediments show that with increasing carbonate content there is a decrease in wet bulkdensity, although the data are very scattered and the trend is poorly defined. Data from continental shelf sediments show that with increasing proportions of 'fine-grained' (<631.1m) sediment fraction, there is an increase in porosity. Continental slopesediments show no clear relationship between the porosity of the sediments and thepercentage of 'fine-grained' (< 6311m) sediment fraction. For continental shelf sediments, increasing carbonate content is associated with a decreasein the 'fine-grained' (<63 rim) sediment fraction. The continental slope sediments show norelationship between carbonate content and the percent < 63 gm sediment fraction.