A 2-D crustal velocity model has been derived from a 1997 364 km north-south wide-angle seismic profile that passed from Ordovician volcanic and volcaniclastic rocks (Molong Volcanic Belt of the Macquarie Arc) in the north, across the Lachlan Transverse Zone into Ordovician turbidites and Early Devonian intrusive granitoids in the south. The Lachlan Transverse Zone is a proposed west-northwest to east-southeast structural feature in the Eastern Lachlan Orogen and is considered to be a possible early lithospheric feature controlling structural evolution in eastern Australia; its true nature, however, is still contentious. The velocity model highlights significant north to south lateral variations in subsurface crustal architecture in the upper and middle crust. In particular, a higher P-wave velocity (6.24-6.32 km/s) layer identified as metamorphosed arc rocks (sensu lato) in the upper crust under the arc at 5-15 km depth is juxtaposed against Ordovician craton-derived turbidites by an inferred south-dipping fault that marks the southern boundary of the Lachlan Transverse Zone. Near-surface P-wave velocities in the Lachlan Transverse Zone are markedly less than those along other parts of the profile and some of these may be attributed to mid-Miocene volcanic centres. In the middle and lower crust there are poorly defined velocity features that we infer to be related to the Lachlan Transverse Zone. The Moho depth increases from 37 km in the north to 47 km in the south, above an underlying upper mantle with a P-wave velocity of 8.19 km/s. Comparison with velocity layers in the Proterozoic Broken Hill Block supports the inferred presence of Cambrian oceanic mafic volcanics (or an accreted mafic volcanic terrane) as substrate to this part of the Eastern Lachlan Orogen. Overall, the seismic data indicate significant differences in crustal architecture between the northern and southern parts of the profile. The crustal-scale P-wave velocity differences are attributed to the different early crustal evolution processes north and south of the Lachlan Transverse Zone.

The Archean Pilbara granitoid-greenstone terrane (GGT) has been the focus of numerous studies on Archaean geology, especially the classic dome-and-basin area around Marble Bar in the east Pilbara. This area has been used as evidence for different tectonic processes, i.e. that vertical tectonics or diapirism was a cause for Archean deformation. This paper provides evidence to support regional horizontal (plate-interaction) stresses as being largely responsible for the compressive deformation of the Pilbara GGT, at least from ca. 3.2 Ga. The relative chronology of meso-to macro-scale structural elements are presented for a number of selected areas across the Pilbara GGT. These locally identified events are correlated with a regional (Pilbara-wide) structural framework of deformation events that are constrained by geochronological and stratigraphic controls. The dome-and-basin geometry characteristic of the east Pilbara was established after 3.2 Ga, and was successively modified by repeated orthogonal extensional and compressive (subhorizontal) events. The result has been a locally complex development of polyphase structural elements with consistent overprinting relationships that can be correlated across much of the Pilbara from 3.2 Ga. Diapirism did not cause these deformation elements, although it may have modified them.

Geoscience Australia, ACRES distribute Landsat Multispectral Scanner (MSS), Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data for a series of epochs or time frames covering Australia. The first epoch is 1972. These data have been produced and provided by the Australian Greenhouse Office (AGO). AGO use the data in their National Carbon Accounting System for monitoring land clearing and revegetation. This data is only available through ACRES and ACRES Landsat Distributors, and not through the AGO. More information is available at <a href="http://www.ga.gov.au/acres/prod_ser/agosuite.jsp">http://www.ga.gov.au/acres/prod_ser/agosuite.jsp</a> This data is available in 1:1M tiles or as a full continental Mosaic. Tiles areas are available at: <a href="http://www.ga.gov.au/acres/prod_ser/agotilemap.jsp">http://www.ga.gov.au/acres/prod_ser/agotilemap.jsp</a>

Linespacing for the survey is 150 metres

Baragwanath Seminar, November 2002.

F2 presentation

Annual Review Dec 2002

Fomin, T., Crawford, A., Arcidiaco, A., and Percival, T., 2002. Refraction/wide-angle seismic studies with vibro source to reveal velocity structure of the Leonora-Laverton tectonic zone, northern Yilgarn. ANSIR Open Day 2002 - Poster.

These data represent the OZCHRON database of physical age determinations of Australian rocks, and the radiogenic isotope ratios used in determining the ages. OZCHRON datasets comprise bibliographic references, analytical data and pooled results for samples derived using the Rb-Sr, SHRIMP, U-Pb, and Sm-Nd age determination methods.

The global downturn in mineral exploration continued in 2001 as planned world-wide expenditure fell to US$2.2 billion from US$2.6 billion in 2000. Australia is the world's leading exploration destination with 17.5% of world mineral exploration budgets. Mineral exploration in Australia in 2000-01 totalled $683.3 million, the first increase (in current dollars) in exploration spending since 1996-97. Western Australia was the leading state for exploration with $424.1 million spent. Gold was the major commodity targeted accounting for 54% of all exploration spending. Access to government-generated geoscientific data and information was improved with the development of the Australian geoscience web portal - <a href="http://www.geoscience.gov.au." target="_blank">www.geoscience.gov.au</a>. Minotaur Resources Ltd reported significant copper-gold-uranium intersections from the Mt Woods Joint Venture, South Australia. Acclaim Exploration NL reported a nickel oxide intersection of 144 m at 1.4% Ni from Wingellina in the Giles Complex, Western Australia. Sipa Resources International NL reported high grade gold intersections at the Waugh prospect, Western Australia, including 15 m at 57.2 g/t Au from 21 m including 3 m at 233 g/t Au from 22 m. Newcrest Mining Ltd further enhanced its Cadia, New South Wales, operation with the first resource estimate of 200 million tonnes at 1.1 g/t Au and 0.41% Cu at the Cadia Far East deposit. Major advances were made in both exploration and project development at the mineral sands projects in the Murray Basin in New South Wales, Victoria and South Australia. Development decisions or commitments to proceed with mine development were made for gold, nickel, mineral sands, diamonds, tantalum and magnesite prospects.