The Australian Geological Survey Organisation (AGSO) through the partnership in the Australian Geodynamics Cooperative Research Centre (AGCRC) and Kalgoorlie Consolidated Gold Mines (KCGM) completed a joint research project to image the crustal structure of the Kalgoorlie region to develop a knowledge of the shallow and deep structures, tectonics, and fluid migration pathways. The Australian National Seismic Imaging Resource (ANSIR) was contracted to acquire the seismic data. The project's objectives were to obtain a better understanding of - sub-surface geology at a regional and mine scale - provide more information on regional crustal thickness and major features - stratigraphic and structural architecture of the mineral system - timing and locations of fluid migration pathways The seismic survey obtained 25 km of 10 fold CMP (common midpoint) regional reflection seismic data along two traverses and 8 km of 10 fold CMP high-resolution reflection seismic data along another two traverses. The data are of good quality and similar to both the 1991 and 1999 Eastern Goldfields reflection seismic data to the north and south of the survey area. The major outcome of imaging the four localities included mapping the Golden Mile and Bolder-Lefroy Faults, and the Boorara Shear at depth. This new information indicates the Golden Mile Mine was fed by a suite of relatively minor faults dangling off the major crustal-scale Boorara Shear. The dangling element relates to percolation theory. The detachment surface was imaged on all seismic traverses. Thrust duplexes were interpreted above the detachment surface.

Current geological mapping by the Northern Territory Geological Survey is leading to a much better understanding of the surface geology of the Territory. Less well understood is the geometry of the Northern Territory in the third dimension, although this has been predicted by the construction of cross sections (e.g. on recent 1:250 000 geological maps). At shallow depths, the cross sections can be constrained by drilling results, if available, but deeper levels can only be examined by geophysical techniques such as seismic reflection or magnetotelluric profiling, or by modelling of potential field data. Text of paper presented at the NTGS AGES 2002 Workshop, Alice Springs, 26-27 March 2002.

This report presents results from a pilot study conducted within the northern part of the Great Australian Bight, focusing primarily on the Eyre Sub-basin. The aim of the study was to develop and test a methodology for creating petroleum prospectivity maps based primarily on the extent of sealing lithologies. The Eyre Sub-basin provides a good basis for this study due to the good seismic coverage and lithological data provided from eight ODP holes and an Esso petroleum exploration well (Jerboa-1). Well data are used to determine which sequences contain potential sealing lithologies, while seismic data are used to map out the extent and distribution of potential sealing sequences across the study area. The regional extent of sealing units to their first pinch-out is used as a first-order assessment of petroleum prospectivity. Results from Jerboa-1 show that there is a proven oil source and adequate reservoir facies with seal and trap integrity being the major play risks. Mesozoic sediments provide the primary potential sealing units across this region and have greatest thickness across the Eyre Sub-basin. To the west and north of this sub-basin, the distribution of the Mesozoic sediments is discontinuous, resulting in lower sealing potential. Mesozoic sediments are absent within the Eucla Inlier immediately north of the Eyre Sub-basin, resulting in very low sealing potential. Three categories of petroleum prospectivity have been determined in this study. Good prospectivity has been assigned up to the limits of the thick and continuous Mesozoic sediments in the Eyre Sub-basin. Low prospectivity has been assigned to the western Apollo Shelf, reflecting the reliance on relatively thin and discontinuous Mesozoic seals and the poor seal potential of Tertiary age carbonates. The Eucla Inlier is designated as a non-prospective area due to the absence of Mesozoic sediments and any potential sealing units for Tertiary age reservoirs.

The Palaeoproterozoic to Mesoproterozoic (<1850-<1490 Ma) southern McArthur Basin, Northern Territory, Australia, contains an unmetamorphosed, relatively undeformed succession of carbonate, siliciclastic and volcanic rocks that host the McArthur River (HYC) Zn-Pb-Ag deposit. Seismic reflection data obtained across this basin have the potential to revolutionise our understanding of the crustal architecture in which this deposit formed. These data were collected in late 2002 as part of a study to examine the fundamental basin architecture of the southern McArthur Basin, particularly the Batten Fault Zone, and the nature of the underlying basement. Geoscience Australia, the Northern Territory Geological Survey and the Predictive Mineral Discovery Cooperative Research Centre combined to acquire an east-west deep seismic reflection profile (line 02GA-BT1) approximately 110 km long, commencing 15 km west of Borroloola, and extending westwards along the Borroloola-Roper Bar road to the Bauhinia Downs region (Fig. 1). A short 17 km north-south cross line (02GA-BT2) was also acquired in collaboration with AngloAmerican. The seismic data were acquired through the Australian National Seismic Imaging Resource (ANSIR).

Seismic reflection, seismic refraction and portable broadband data collected within Western Australia's Yilgarn Craton, in particular the Eastern Goldfields Province, are providing detailed images of several of its highly mineralized terranes as well as new insights into the crustal architecture of the region. When the results from these seismic techniques are integrated, the results are providing a better understanding of the structure of the crust and lithosphere beneath the Yilgarn Carton, from the surface to depths in excess of 300 km.

Deep-seismic reflection data across the Archaean Eastern Goldfields Province, northeastern Yilgarn Craton, Western Australia have provided information on the crustal architecture and on several of its highly mineralised belts. The seismic reflection data contain has images of several prominent crustal scale features, including an eastward thickening of the crust, subdivision of the crust into three broad layers, the presence of a prominent east dip to the majority of the reflections and the interpretation of three east-dipping crustal-penetrating shear zones. These east-dipping shear zones are major structures that subdivide the region into four terranes. Major orogenic gold deposits in the Eastern Goldfields Province are spatially associated with these major structures. The Laverton Tectonic Zone, for example, is a highly mineralised corridor that contains several world-class gold deposits plus many smaller deposits. Other non crustal-penetrating structures within the area do not appear to be as well endowed metallogenically as the Laverton structure. The seismic reflection data have also imaged a series of low-angle shear zones within and beneath the granite-greenstone terranes. Where the low-angle shear zones intersect the major crustal-penetrating structures, a wedge shaped geometry is formed. This wedge geometry forms a suitable fluid focusing geometry where upward to sub-horizontal moving fluids are focused and then distributed into the nearby complexly deformed greenstones.

The Stuart Shelf overlies the eastern portion of the Gawler Craton. This part of the Gawler Craton is South Australia's major mineral province and contains the world-class Olympic Dam Cu-U-Au deposit and the recent Cu and Au discovery at Prominent Hill. The Stuart Shelf is several kilometres thick in places. As such, little is known of the crustal structure of the basement, its crustal evolution or its tectono-stratigraphic relationship to adjacent areas, for example the Curnamona Province in the east. There has been much effort applied to advancing our understanding of basement, mainly through the use of potential field data and deep drilling programmes; though drilling has proved very costly and very hit and miss. The Stuart Shelf area needs new data and methods to bring our knowledge of it to the next level of understanding. At a Gawler Craton seismic planning workshop held in July 2001, stakeholders from industry, government, and university stakeholders identified several criteria fundamental to undertaking any seismic survey within the Gawler Craton. These were - Location of seismic traverse across a known mineral system in order to improve understanding and enhance knowledge of the region's mineral systems. Access to surface and/or drill hole geological knowledge to link geology data with the seismic interpretation. Good coverage of potential field data, and Potential for the seismic data to stimulate area selection and exploration in the survey region.

Overview of the deep crustal seismic surveys conducted by Geoscience Australia through the Onshore Energy Security Program since its commencment in 2006 up to September 2009.

This data set consists of processed seismic reflection data for line 01AGS-NY1 from the 2001 Northern Yilgarn seismic survey (L154), Western Australia. Line 01AGS-NY1 commenced in the Yilgarn Craton (Leonora) and extended to the east into the Officer Basin (east of Lake Yeo). The data were acquired by the Australian National Seismic Imaging Resource (ANSIR) using vibratory sources at a nominal 60 fold coverage. The seismic data are provided as SEG-Y files of stack and migrated data to 4 seconds and 18 seconds two-way time, at a sample interval of 4 milliseconds. CDP range is 1985 to 20860 with 20 metre CDP interval. SEG-Y header information, CDP coordinates as eastings and northings, and a pdf image of the migrated 18 second seismic section are also included. The line, migrated section images and further information on this data can be obtained from the <a href="http://www.pmdcrc.com.au" target="_blank">pmd*CRC</a> website.

New 2D seismic data acquired in the Mentelle Basin by Geoscience Australia in 2008-09 has been used for a seismic facies study of the post-rift succession. The Mentelle Basin is a large deep to ultra deep-water, frontier basin located on Australia's southwestern margin about 200 km southwest of Perth. The study focused on the post-rift sequences deposited following the breakup between Australia and Greater India. Stratigraphic wells DSDP 258 and DSDP 264 provide age and lithological constraints on the upper portion of the post-rift succession down to mid-Albian strata. The depositional environment and lithology of the older sequences are based on analysis of the seismic facies, stratal geometries and comparisons to the age equivalent units in the south Perth Basin. Fourteen seismic facies were identified based on reflection continuity, amplitude and frequency, internal reflection configuration and external geometries. They range from high continuity, high amplitude, parallel sheet facies to low continuity, low amplitude, parallel, subparallel and chaotic sheet, wedge and basin-fill facies. Channel and channel-fill features are common in several facies as well as a mounded facies (probably contourite) and its associated ponded turbidite fill. A progradational sigmoidal to oblique wedge facies occurs at several stratigraphic levels in the section. A chaotic mound facies, probably comprising debrite deposits, has a localised distribution. Seismic facies analysis of the post-rift sequences in the Mentelle Basin has contributed to a better understanding of the depositional history and sedimentation processes in the region, as well as provided additional constraints on regional and local tectonic events.