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  • The objectives of hydrogeologically mapping the Murray basin were to generate a set of maps at 1:250 000 scale to: - show the influence of groundwater on land salinisation and surface water salinity - delineate useable groundwater resources - highlight present and potential salinity hazard and - enhance community awareness and understanding of groundwater systems and processes and provide a groundwater data-base for the Murray Basin to facilitate land and water resource management decisions. The production of the Murray Basin Hydrogeological Map Series was a major coordinated Government action in the management of groundwater to combat degradation through salinisation and enable sustainable land and water use in the Murray Basin. The Hydrogeological Map Series was a collaborative effort between the various water authorities of South Australia, Victoria and New South Wales. Explaining this product in detail is an article by Evans, W.R. 1992, "The Murray Basin Hydrogeological Map Series", Water pp. 20-23.

  • This stunning image map of the Cocos islands provides an informative look at this Australian Territory. Derived from a SPOT satellite image, it includes a description and history of the island, location map and numerous colour photographs. Spot multi spectral image single sided poster. Sold through Geoscience Australia`s Sales Centre or our map retailers, located throughout Australia.

  • Total magnetic intensity data measures variations in the intensity of the Earth's magnetic filed caused by the contrasting content of rock-forming minerals in the Earth's crust. The data are collected on airborne geophysical surveys conducted by Commonwealth, State & NT Governments and the private sector.

  • The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium, uranium and thorium. The data are collected on airborne geophysical surveys conducted by Commonwealth, State & NT Governments and the private sector.

  • The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium, uranium and thorium. The data are collected on airborne geophysical surveys conducted by Commonwealth, State & NT Governments and the private sector.

  • The 1:100 000 scale geological map series, that now covers a significant proportion of Australia, has been produced by AGSO and its counterpart state bodies. The quality of maps has improved steadily over the years. Modern maps are produced with the aid of satellite images and aircraft-obtained magnetic and gamma-ray images.

  • The Munni Munni Complex is a boat-shaped layered intrusion, divided into a lower ultramafic 'keel', up to 1850 m thick, overlain by a gabbroic sequence at least 3000 m thick. The top of the ultramafic series is marked by a 20-80 m thick porphyritic websterite zone (PWZ), that extends laterally to form a 200 m thick layer of pyroxenite along the walls of the intrusion. Platinum-group element (PGE)-enriched disseminated sulphides occur within the top 20 m of the PWZ unit along its entire exposed strike length, with maximum total PGE grades up to 8 ppm over 500 mm widths. The PWZ marks a pronounced discontinuity in mineral composition trends within the intrusion, between uniform relatively high Mg# and Cr-rich pyroxenes in the main part of the ultramafic series, to gabbroic cumulates showing a monotonous trend of declining Mg# due to closed system fractionation in a large chamber. The Cr2O3 content of cumulus augite shows a dramatic drop from about 0.2% to less than 0.05% over less than 4 m near the top of the PWZ. Disseminated cumulus sulphides are abundant within an interval from 5 m above the gabbro contact to 15 m below it. Two sulphide components are present. The first is a relatively PGE-poor component, characterized by coincidence of peak Cu, Ni, S and PGE abundances. The second is a variable composition component, strongly PGE enriched at the base and depleted at the top, characterized by systematic offsets between the peak PGE and Cu abundances. The 'offset' sulphides always occur above the 'coincident' sulphides, and their first appearance corresponds to the sudden drop in Cr2O3 content of clinopyroxene within the PWZ. The coincident sulphides are interpreted to have formed by batch equilibration of sulphide liquid droplets during the magma mixing event that produced the PWZ. The offset sulphides formed subsequently by fractional segregation and gravity settling of sulphide liquid droplets from a stagnant hybrid melt layer dominated by the gabbroic component. The observed lateral distribution of PGE-rich sulphides in the PWZ is inconsistent with derivation of PGE from trapped liquid in underlying cumulates and provides strong evidence for the existence of primary PGE-enriched cumulus sulphide liquid.

  • In early 1987, scientists aboard R.V. Rig Seismic carried out a 29 day research cruise over the Otway Basin and the Sorell Basin of the west Tasmanian margin, to provide new geological, geochemical and heatflow data, in an area with considerable petroleum potential. Altogether, 130 sampling stations were occupied using dredges, corers, grabs and a heatflow probe. Among the rocks recovered were: Palaeozoic volcanics and metasediments; Late Cretaceous sandstones, siltstones and mudstones; early Tertiary siltstones; and late Tertiary carbonates. All samples were taken along seismic profiles, so that the results can be easily incorporated into the regional geological framework. In general, the further down the continental slope, the older the rocks. Palaeontological results indicate that there has been very considerable post-Eocene subsidence of the slope. A great variety of Quaternary sediments were recovered, and these have allowed a detailed sedimentation model to be developed. Heatflow calculations from 20 stations suggest that the present zone of thermal maturation of hydrocarbons is 2-4 km deep. Headspace gas analyses of many cores indicate that thermogenic hydrocarbons are widespread, with particularly high readings in both the eastern and the western Otway Basin and on the west Tasmanian margin. Thus, mature hydrocarbon source rocks must also be widespread.