Tuggeranong - geomorphology map

No abstract available

22-1/H52-08/6 Vertical scale: 1000

Legacy product - no abstract available

-33 to -33.33 degrees 22-3/I55-7/1-3/1 Contour interval: 10

High-quality, regional seismic data collected on the continental margin of southern New South Wales indicate that the margin lacks major basin development, consistent with its interpretation as an upper plate margin. The most striking structural feature is a mid-slope graben or half graben which is bounded on its eastern (seaward) side by a westerly-dipping fault system and a basement ridge. The half-graben contains up to 2.2 seconds TWT (~2500 m) of sediment, including syn-rift deposits possibly as old as Late Jurassic. A seaward-thickening wedge of sediment overlies a generally flat basement surface beneath the shelf. This contrasts with large areas of the lower continental slope which are essentially free of sediment. Sediment thicknesses beneath the Tasman Sea abyssal plain reflect basement structure. The greatest thickness occurs next to the foot of the slope where sediment loading has produced flexuring in either oceanic or thinned-continental crust. Overall, the petroleum potential of the margin (excluding the pre-rift Sydney Basin rocks) appears to be low.

Surveys were carried out in East Java, Indonesia, to determine the nitrate concentrations of (a) household well waters in selected settlements, (b) certain other waters, and (c) selected soil profiles. Nitrate concentrations in the well waters ranged from zero to 304 mg/ L, with marked differences between regions and between wells within a given settlement. The patterns of nitrate concentrations within villages as well as in and around rice fields appear to exclude the application of nitrogen fertilisers to rice fields as a significant cause of the nitrate observed in well water. Of all the nitrate sources considered, the main ones are likely to be food and feed brought from outside into villages, and which, after ingestion, are excreted in a localized way inside them, giving rise to large spatial variation in nitrate concentrations.

Fresh to brackish groundwaters in the range of 250 to 2250 mglL occur in fractured bedrock aquifers beneath dryland salinity sites at Yass in the Southern Tablelands of New South Wales. The fractured bedrock in these catchments comprises marine, early Paleozoic slates, shales and sandstones in Dicks Creek and Williams Creek catchments, and porphyritic dacite and rhyodacite in Spring Creek catchment. The groundwaters are known to originate from recent meteoric waters. The waters represent various hydrochemical types, generated by chemical processes through water-rock interactions along their flow paths. The present chemical composition of major cations and anions in groundwaters from these catchments is derived from the following processes: 1. water-rock interaction in recharge zones where dissolution of minerals and oxidation processes occur, 2. ion-exchange and reverse ion exchange reactions with clay where it is present in fractures and veins in the bedrock, and 3. microbially mediated reactions with organic matter which produce very low redox potentials.

Society increasingly demands that resource management decisions reflect ecological sustainability criteria. The current strain on the global environment makes it essential that environmental factors are considered along-side economic and social factors. This places increased emphasis on resource management as opposed to resource exploitation. Parallel to this trend is the requirement that Government policies and programs be more accountable; politically, economically and socially. This is leading, within Australia, to the use of rigorous performance indicators, as measures of the success of management practices. Australia, through various natural resource agencies, is moving towards more sustainable water resources management. The knowledge and information requirements to support these initiatives are, at present, ill-defined, but are likely to prove formidable. This means that public policy relating to water resources management will be framed with inadequate scientific information. The Australian Geological Survey Organisation is developing an Australian Groundwater Quality Assessment Program, within the framework of the National Landcare Program and as part of the National Water Quality Management Strategy. This Program will seek to cooperatively meet the information needs of the Strategy by a number of survey and research studies.

Improvements in agricultural production help sustain the worlds burgeoning population. The question is whether agricultural technologies degrade primary soil and water resources. Sulfonylurea herbicides provide a good example of the impact of a technical innovation. Higher more-dependable wheat yields were achieved over the entire Australian wheat belt after the introduction of the sulfonylurea herbicides. More recently, farmers have expressed concern about limited recropping options and the accumulation of sulfonylurea residues in some soil types. A risk/benefit balance sheet for residual sulfonylureas indicates that benefits of sulfonylurea use far outweigh risks, particularly compared with an alternative mechanical weed control option. The overall profile of sulfonylurea herbicides fits well with the characteristics needed for sustainable farming systems. However, two potential problems were identified for sulfonylurea use on alkaline sodic soils: injury of highly susceptible legumes from sulfonylurea carryover and sulfonylurea leaching into groundwater. The risk depends largely on the amount and distribution of rainfall. Thus, problems can be averted if geographical information systems/herbicide simulation models and seasonal weather forecasts are combined to provide site specific recommendations.