L048 Southern Surat Basin seismic reflection and refraction survey, QLD, 1961

Brief description

During 1961 in the southern part of the Surat Basin a seismic party from the Bureau of Mineral Resources surveyed two main traverses by means of seismic reflection and refraction methods; the first was in an east-west direction between Yelarbon and St George and the second was in a north-south direction between Meandarra and Nome. The main purposes of the survey were to find whether the Bowen Basin Permian sediments extend as far south as the latitude of Goondiwindi and whether the Bowen Basin in Queensland and the Sydney Basin in New South Wales formed a continuous region of sedimentation during the Permian period. The east-west seismic traverse indicated a trough of sediments of greatest thickness,tabout 14,800 ft beneath Toobeah; the trough is bounded on the eastorn side at Goondiwindi by a fault down-thrown more than 7000 ft to the west and is bounded on the western side by a series of step.-faults beneath Bungunya and Talweod. The results along the north-south traverse indicated that the trough beneath Meandarra, which represents the southern extension of the Bowen Basin, continues south to Toobeah. The nature of the link, if any, between the Bowen Basin and the Sydney Basin was not established. On the eastern side of the Surat Basin, seismic results indicated that the rocks beneath the Mesozoic sediments are stratified and probably metamorphic. A shelf area between Talweod and St George has about 6000 ft of sediments above a Drobablo metamorphic 'basement'. An anticlinal structure with a dip-reversal of about 1000 ft throw was located between Goondiwindi and Toobeah.

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Maintenance and Update Frequency: asNeeded

Statement: During 1958, 1959, and 1960, a seismic party from the Bureau of Mineral Resources worked in the Surat Basin and by 1960 had completed a reconnaissance seismic reflection traverse from Roma through Surat to Tara and Jondaryan 25 miles south-east of Dalby. The result of this regional traverse indicated that between the shelf areas of the Roma/Surat area and the Dalby area there was a trough with up to 20,000 ft of sediments (Lodwick & Watson, 1960 and Smith & Lodwick, 1962). The trough was interpreted as an extension of the Bowen Basin plunging beneath the Mesozoic sediments of the Surat Basin. A major uplift was discovered near Cabawin with strong faulting and buried erosional surfaces and was called the Cabawin Anticline (Lodwick and Watson, 1960). The discovery of the major uplift near Cabawin has led to a great deal of seismic and aeromagnetic surveying since 1960 by Union Oil Corporation, in conjunction with Kern County Land Company and the Australian Oil and Gas Corporation, much of this geophysical exploration was subsidised by the Commonwealth Government. The geophysical exploration has subsequently led to the drilling of Cabawin No. 1 well in which oil was discovered, Cabawin East No. 1 which was dry, and the Moonie No. 1, 2, and 3 wells in which oil was also discovered. In 1961, the Bureau planned another seismic reconnaissance survey in the southern part of the Surat Basin with the following objectives: (a) to survey a roughly east-west reconnaissance traverse in the southern part of the Basin, in order to determine the structure and sedimentation of the Basin, (b) to extend a reconnaissance traverse south to determine the southern margin of the Basin, assuming the east-west reconnaissance line showed that a large thickness of sediments exists, (c) to survey a reconnaissance traverse north, towards Meandarra, to tie the work in the southern part of the Basin to that done in the north during 1959 and 1960. It was expected that the east-west traverse would indicate whether the trough of sediments discovered between Glenmorgan and Goranba extended southward. It is not clear whether the sedimentary trough beneath Meandarra extends far enough south to join the Sydney Basin in NSW or whether a basement 'high' separates the two basins.