As part of Geoscience Australia's Southwest Margin Project, two major marine surveys were undertaken (from October 2008 to February 2009) to investigate the resource potential of deep-water frontier areas on the southwest Australian continental margin. 1. Southwest Australian Margin Regional Marine 2D Seismic Survey (S310) - Areas covered by the seismic survey include the Mentelle Basin, North Perth Basin (Zeewyck and Houtman Sub-basins), Southern Carnarvon Basin and the Wallaby Plateau. Data acquired: 7300 kilometres of 2D seismic (12 second record length, 8 km solid streamer), gravity and magnetic data. In addition to the new seismic reflection data, Geoscience Australia has reprocessed selected open-file industry seismic lines in the offshore Northern Perth Basin (11,700 line km) that provides ties to most wells in the Abrolhos and Houtman sub-basins. 2. Southwest Australian Margin Marine Reconnaissance Survey - The marine reconnaissance survey investigated the geology and marine environments of the offshore North Perth and Southern Carnarvon Basins and the Wallaby Plateau. Data acquired: multibeam swath bathymetry (230,000 km2), gravity and magnetics (25,000 line km), sub-bottom profiler (25,000 line km), geological samples (190 rocks from 53 dredge sites)

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.

The new acquisition of multibeam bathymetry data along with potential field, seismic data and sediment and rock samples has provided a large quantity of new data in the Northern Lord Howe Rise. A detailed study of the relationships between the surface and sub-surface features over the Capel and Faust basins suggests that seafloor deformation is linked to the underlying basement architecture. Numerous seafloor and sub-surface geological features have been identified and mapped over the study area. Their nature, distribution and relationships have been analysed to propose their formative mechanisms. Most of these features are related to buried igneous intrusions and fluid flow either located within depocentre megasequences or along basement bounding faults. The co-genetic geological features indicate that fluid flow is mainly driven by igneous activity. The ongoing fluid flows, after each magmatic pulse has re-utilised pre-existing fluid conduits. Major depocentres have been identified over the study area and could be prospective for petroleum exploration. Potential source, reservoir and seal rocks are likely to be present in the capel and Faust basins. Volcanic activity has driven the geology and fluid flow over the study area since at least the Upper Cretaceous and has to be considered when assessing the petroleum prospectivity of the Capel and Faust basins and also elsewhere in the Lord Howe Rise.

A new 460 km long transect combines 6-12 fold explosive and 60 fold vibroseis data, proving that it is possible to re-use old, low fold seismic data by utilizing new processing techniques. We demonstrate comparability in resolution of reprocessed dynamite and new vibroseis data. Reprocessing of the dynamite data using a vertical stacking technique that simulates DMO corrections, followed by detailed velocity analysis, has resulted in an improved seismic section that images dipping structures not detected in the original processing.A new 460 km long transect combines 6-12 fold explosive and 60 fold vibroseis data, proving that it is possible to re-use old, low fold seismic data by utilizing new processing techniques. We demonstrate comparability in resolution of reprocessed dynamite and new vibroseis data. Reprocessing of the dynamite data using a vertical stacking technique that simulates DMO corrections, followed by detailed velocity analysis, has resulted in an improved seismic section that images dipping structures not detected in the original processing. Several deep penetrating shear zones in the Broken Hill block dip mostly to the SE, and link to a shallow thrust belt located further to the west. Because of the large depth of penetration, these shear zones may have conducted fluids from deeper levels, which has important implications for mineral exploration.

Presentations from the SA Seismic and MT workshop 2010.

Legacy product - no abstract available

No abstract available

We have made a step forward in developing a methodology for processing, interpreting and presenting near-vertical reflection, wide-angle reflection and refraction seismic data and velocity information derived from these data sets within a unified approach. Wide-angle reflection and refraction data that we used to supplement conventional CDP (near-vertical reflection) data were recorded by ocean-bottom (OBS) seismographs on the Australian North West Shelf during the survey undertaken by AGSO along 5 profiles of total length 2764 km. Data in these experiment were recorded to maximum offsets of 300 km.

Between 1990 and 1994, AGSO - Geoscience Australia acquired approximately 35,000km of regional, mostly deep (commonly 15s record length), 2D seismic reflection data along the northern and north-western continental margins of Australia. These data were shot primarily to provide a structural and tectonic framework to assist petroleum exploration companies in their search for hydrocarbons in the region, as well as an aid to understanding the margin's geological evolution. This CD contains line drawings of interpretations of all of the lines that compose the Geoscience Australia's regional grid. The interpretations (horizons and faults) were made by an external contractor to Geoscience Australia, IKODA Pty Ltd, using Landmark software, and build on previously published Geoscience Australia work of parts of the grid (e.g. papers in Purcell & Purcell, 1994) as well as tying to Geoscience Australia-sponsored detailed NW Shelf and Timor Sea high-resolution seismic studies.

The 2008 Rankins Springs Seismic Survey was a joint initiative by Geoscience Australia and NSW Department of Primary Industries under the Onshore Energy Security Program (OESP) in the under-explored southeastern Darling Basin. Regional acquisition parameters of 300 channels, 40 m group interval and 80 m vibration point interval nevertheless allowed detailed imaging of a 3 second (TWT) thick sedimentary sequence in the Yathong Trough. Use of three 12 second vari-sweeps from truck mounted Hemi 50 (50,000 lb) vibrators provided sufficient energy to image from immediately below regolith to the Moho. The sweep frequency ranges 6 - 64, 10 - 96 and 8 - 80 Hz were chosen both for deep penetration and high resolution in the sedimentary section. In-field processing produced a high quality preliminary section on a daily basis using an iterative process of automatic residual statics calculation on a deep gate and interactive stacking velocity analysis. Both automatic statics and stacking velocity were essential for successful imaging, but velocity was more important, as initial estimates based on first arrival velocities produced a degraded section. The field seismic section clearly shows a fault bounded trough, with evidence of compressional structures in the upper part and hints of underlying older sedimentary basins. The in-field stacking velocity analysis also provided immediate evaluation of the maximum depth of the trough, namely 6 km, deeper than expected. Efficient in-field processing allows early notification to project partners of a successful survey, facilitating future planning, and provides a sound basis for streamlined subsequent processing.