As at January 1993, nineteen hydrocarbon accumulations, six of which are commercial, have been discovered in the Canning Basin. The commercial accumulations occur in Permian to Devonian reservoirs on an area of relatively shallow basement (Lennard Shelf) flanking the northern margin of the Fitzroy Trough. Oil is produced from Famennian reefs, associated drape structures, and four-way dip closures in Permo-carboniferous, Grant Group and Anderson Formation sandstones. The most likely sources of these hydrocarbons are Late Devonian and Carboniferous marine shales in the Fitzroy Trough kitchen area. The small size of the accumulations in the Canning basin (less than 0.5 million barrels of recoverable oil) precludes the development of large infrastructure projects. Oil is trucked to the storage and shiploading facilities at Broome and then shipped to the Kwinana oil refinery in Western Australia. On the southern margin of the Fitzroy Trough, oil and gas have been recovered from a transgressive Ordovician sequence of sandstones shales and carbonates. Although the Ordovician has yet to yield a commercial discovery, Devonian reef plays in the overlying section may enhance the attractiveness of Ordovician objectives in this area. To date, exploration effort in the basin has been largely directed to the northern, onshore Canning Basin. The offshore Canning and the Kidson Sub-basin remain underexplored. Higher risk plays in these areas have yet to be adequately tested.

In this paper, petroleum hydrocarbon contamination at two field sites is characterised extensively to provide data for risk assessment, and remediation design and monitoring. A dissolved hydrocarbon plume in groundwater, emanating from a leaking underground storage tank, has been characterised in detail. The spatial and temporal variations of dissolved BTEX (benzene, toluene, ethylbenzene, xylene) compounds and naphthalene within the plume have been mapped. The plume extends greater than 420 m down hydraulic gradient from the site, is less than 3 m thick, and less than 40 m wide. Seasonal inundation of the residual non-aqueous phase liquid (NAPL) gasoline in the soil profile near the point of leakage, apparently provides an ongoing source for dissolved BTEX compounds in groundwater. Remediation would need to target the residual NAPL. Residual NAPL contents in the near-water table zone of a diesel/kerosene fuel spill also have been quantified. The NAPL contents of recovered cores have been correlated with soil particle size distributions, water table fluctuations and saturation-pressure (S-P) relations of soil cores. Cored profiles typically show residual NAPL contents over 0.5 to 1 m depth intervals with peak NAPL contents up to 26 % by weight, at or immediately above the water table. The mobility of the NAPL in these soil materials has been investigated. Such data have been essential for the planning, implementation and effective monitoring of a remediation strategy that targets this thin NAPL zone.

Legacy product - no abstract available

Legacy product - no abstract available

Kalgoorlie-Kurnalpi WA Special Regolith-Landform map 1:250 000

The 3rd Australian Geomagnetism Workshop continues the tradition of previous meetings in this series, held in Canberra in 1985 and 1987, by providing a focus for the wide range of scientists in the Australian region who share a common interest in geomagnetism. The aim of the meeting is to bring together those who use geomagnetic information to take advantage of the many applications of geomagnetic phenomena, those who generate that information, and those who investigate the behaviour and origin of the geomagnetic field. The quality and diversity of the abstracts herein bears testimony to the vigorous state of pure and applied geomagnetism research in Australia.

Legacy product - no abstract available

Product Specifications Coverage: Partial coverage, predominantly in northern Australia, along major transport routes, and other selected areas. About 1000 maps have been published to date. Currency: Ranges from 1968 to 2006. Coordinates: Geographical and UTM. Datum: AGD66, new edition WGS84; AHD. Projection: Universal Transverse Mercator UTM. Medium: Paper, flat copies only.

U-Pb zircon SHRIMP ion-microprobe ages are presented for five Proterozoic igneous rocks from the Georgetown Province of northeastern Queensland. Four of these are interpreted as the igneous crystallisation ages of the Croydon Volcanic Group (1548±18 Ma), Lighthouse Granite (1561±10 Ma), Digger Creek Granite (1554±10 Ma), and Mount Hogan Granite (1549±25 Ma). Most of the zircon within the Forest Home Trondhjemite is apparently xenocrystic, being rounded cores that crystallised at 1650±17 Ma; the time of emplacement is not known with certainty, but is thought to be better represented by a 1553±46 Ma Rb-Sr isochron age. The U-Pb zircon emplacement ages are internally consistent in constraining the age of a prograde, intense tectonothermal event (D2) in the province to 1554±10 Ma. This is about 80 Ma older than a previous estimate for the age of this event, based on the correlation of Rb-Sr whole-rock isochron ages and the development of a penetrative (S2) fabric. The use of that particular Rb-Sr technique in terranes of this type should therefore be treated with considerable caution.

Surveys of groundwater quality have been carried out in alluvial aquifers of the Kathmandu valley, Nepal, and a wide range of parameters studied. The natural groundwaters are characterised by high concentrations of iron, manganese, ammonia and carbon dioxide. The presence of coliform bacteria in many wells indicates the need for pollution control. Rapid population growth and urbanisation, and an increasing concentration of industries, are contributing to degradation of groundwater quality. Monitoring programs leading to increased public awareness and management action are necessary at this stage in development.