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Updated:
26 August 2005
North Australia Project: Early Proterozoic foundationsSeismic profilingObjectiveTo reprocess, document and archive the existing Central Australian deep seismic lines recorded by Bureau of Mineral Resources (BMR) in 1985 through the Amadeus Basin, Arunta Province and Ngalia Basin in order to improve the quality of these seismic sections. The improved sections will allow an improved interpretation of the imaged structures in the various regions and will facilitate the development of a three-dimensional geological history. BackgroundProcessing technology and software has improved significantly since the 1985 deep seismic reflection data was first processed. Initial interpretations for the seismic lines indicated substantial middle and lower crustal structure. Therefore, reprocessed sections will be much improved and will provide the project with valuable information on the third dimension of the southern NAR. A three-dimensional understanding of an area is critical to understand the regional geodynamic evolution. Better interpretations of the regional crustal structure allow better development of a model for tectonic evolution. The reprocessing will be done to enhance both the shallow and deep structures. The shallow processing will focus on:
As part of the wider study into the basement of the NAR, and its relationship to the surrounding orogenic belts, Geoscience Australia will join with the Northern Territory Geological Survey (NTGS) in identifying geological transects suitable for seismic reflection techniques. Tanami mineralisationObjectiveTo provide specialist input to improve the understanding of mineral systems in this significant gold province using a combination of fluid inclusion analysis, geochronology, structural analysis, whole rock geochemistry, mineral paragenesis, wall rock alteration and thermodynamic modelling. This will lead to a better understanding of geological controls on ore deposition, which will assist in exploring for the deposits in the Tanami and in the adjacent North Arunta. Background:The Tanami Region is one of the most important new Au producing areas in Australia. NTGS commenced detailed studies of the gold deposits in June 1999 with Australian Geological Survey Organisation (AGSO) joining in July 2000 to provide specialist expertise in the Laser Raman Microprobe and fluid inclusion analysis and thermodynamic modelling. Prior to the late 1980s production from the Tanami Region was small, but since then a number of significant new deposits have been found, including the Ground Rush and Coyote deposits. Despite this productivity, the amount of research into ore controls is small, especially when compared to well studied areas such as the Eastern Goldfields in Western Australia. This module builds upon the ongoing NTGS Tanami Region project to establish fundamental controls on mineralisation. Current exploration models in the Tanami Region stress proximity to granitoids and their thermal aureoles (Tunks and Marsh, 1998, AusIMM Mon. 22, p. 443-448; Smith et al., 1998, AusIMM Mon. 22, p. 449-459). However, fundamental premises for this model remain untested. For instance, the mineralisation is undated, so its temporal relationship to granitoids is unknown. Furthermore, although some fluid inclusion data exist, these data are insufficient to determine the relative importance of magmatic-hydrothermal fluids to ore genesis. Hence, fundamental questions remain about the genetic and exploration models applied to Au deposits in the Tanami Region. This module will test and refine the granite-related model and assess structural and geochemical controls on mineral deposition using fluid inclusion analysis, geochronology (Ar-Ar, Re-Os and other techniques), structural analysis, whole rock geochemistry and isotope geochemistry. An important aspect of this module is the focus on the mineral system approach, which will emphasise processes outside of the immediate ore environment. Caption: The Callie gold mine at the Dead Bullock Soak goldfield in the Tanami region. 1.2 Moz Au was won from the open cut pit and the remaining underground resource is 3.9 Moz Au. Tennant inlier gravityObjectiveTo assist exploration in the Tennant Inlier by the provision of semi-detailed gravity. Background:Copper-gold deposits of the Tennant Inlier are perhaps the oldest of a clan of ironstone-hosted Cu-Au deposits that include deposits from the Eastern Succession of the Mt Isa Inlier, the Curnamona Craton and possibly parts of the Gawler Craton. Although these deposits have been extensively studied over the years, the third dimension of the regional geologic setting is not well constrained. To assist in constraining this third dimension, a semi-detailed gravity survey will be conducted in the Tennant Creek area. These results will be used in combination with recent aeromagnetic data to model the 3D geologic architecture of this area. Related links |