In October and November 1959 a seismic party from the Bureau of Mineral Resources carried out a seismic survey in the Surat Basin, Queensland at the request of Australian Oil and Gas Corporation Ltd. A traverse extending from Surat eastward to within 10 miles of Tara was shot in five-mile sections of continuous reflection profiling with approximately five-mile intervals between the sections.^In addition two refraction traverses were shot near Surat to record velocities and depths of as many horizons as possible. Reflections were of fair to good quality throughout the survey and it was possible to correlate bands of reflections from one five-mile section to the next with considerable certainty. Over most of the traverses four reflecting horizons were followed, and in a few places reflections were obtained from a still deeper fifth horizon. The reflection survey revealed a wide basin between Surat and Cabawin (about 70 miles east of Surat), with its maximum thickness of sediments under Meandarra. The sediments there appear to be at least 19,000 ft thick. A marked anticline was discovered near Cabawtin. The refraction survey, using the "Depth Probing" method, revealed a refractor with a calculated velocity of 20,180 ft/sec situated about 1000 ft below the fourth reflecting horizon.

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.

The Undilla Basin, in north-western Queensland, is a small sedimentary basin containing Cambrian limestones which adjoin the widespread but undated CamoowJal Dolomite to the West. In the latter part of 1961 the Bureau of Mineral Resources, Geology and Geophysics did a brief reconnaissance seismic survey lasting about seven weeks in the Undilla Basin. This Record describes briefly the work done and results obtained. The occurrence of limestone near the surface throughout the basin presented difficult problems in the application of the reflection and refraction seismic methods but some progress was made towards the solution of these problems.

Aeromagnetic and gravity surveys were made in the Tambo-Augathella area by Magellan Petroleum Corporation in 1959 and 1960 respectively. A probable fault shown in the magnetic interpretation is almost coincident with a zone of steep gravity gradients which was interpreted as indicative of a fault or of steeply dipping strata. However, the normal gravity interpretation would indicate a deeper cross-section to the south-east of this zone, whereas the magnetic interpretation suggests that the fault is downthrown to the northwest. The present survey was undertaken by the Bureau of Mineral Resources to find out which interpretation was the more probable. A reflection seismic traverse was shot at right angles to the closed gravity 'high' and across the zone of steep gravity gradients. Results show that the closed gravity 'high' is the expression of an anticline and that the zone of stoep gravity gradients is caused by steep dip to the south-east on the flank of the anticline. The gravity interpretation is therefore found to be more representative of actual conditions.

A seismic survey, consisting of a main north-south reflection traverse and several short supplementary reflection and refraction traverses, was made in the Gosses Bluff area, of the Amadeus Basin,Northern Territory by a seismic party of the Bureau of Mineral Resources, Geology and Geophysics between March and July 1962. The purpose of the survey was to obtain information on the lli.ssionary Plain Syncline, the Gosses Bluff uplift; the fault at the northenl flank of the Gardiner Range, and the tectonic features relative to the Archaean/sedimentary contact at the northern edge of the Missionary Plain. The seismic reflection method proved to be an excellent exploratory tool in the undisturbed parts of the sedimentary basin. The Missionary Plain Syncline was shovm. to have a maximum thickness of sediments of 33,000 ft, nine miles north of Gosses Bluff. The results indicate that Gosses Bluff is a diapiric structure of the salt dome type, where the Proterozoic Bitter Springs Limestone has provided the necessary mobile material. The Gardiner Range Fault was shown to be overthrust from the south vdth a hade of 15 to 20 degrees. The problem regarding the Archaean/sedimentary contact was not solved.

Between April and July 1962, a seismic party from the Bureau of Mineral Resources, Geology and Geophysics made a seismic reflection and refraction survey in the Moree area of New South Wales. The main purpose of the survey was to investigate whether the southern extension of the Bowen Basin beneath the Great Artesian Basin from Meandarra to Toobeah continued as far south as Moree and joined the Sydney Basin. Three east-west traverses were shot using a method of reconnaissance reflection shooting, the first near Dolgelly Bore, the second through Moree, and the third through Bellata. The third traverse was extended eastward as far as the Horton River to investigate the Hunter-Bowen Thrust zone. In addition, three north-south refraction traverses were shot in the middle, and on both ends, of the east-west traverse through Moree. A north-south reflection traverse was shot north of Dolgelly Bore.Results in the Moree and Bellata areas were of poor quality and in the Bellata area in particular, owing to surface basalt flows, little information was obtained. The Hunter-Bowen Thrust area was not distinguished by the seismic work. The seismic results indicated that the trough of sediments extending southwards through Dolgelly Bore was at least 7500 ft deep south of Dolgelly Bore. The eastern margin of the trough is probably an overthrust fault. In the Moree area, two troughs were indicated, viz. the Biniguy Trough in the east where about 7000 ft of sediments was estimated separated by the Pallamallawa Ridge from the Moree Trough in the west where about 11,000 ft of sediments was estimated. Poor results in the Bellata area failed to indicate whether the Moree Trough joined the Sydney Basin.

Seismic refraction investigations were made at five sites in the vicinity of Alice Springs, Northern Territory, by the Bureau of Mineral Resources in August 1962. This work was done, at the request of the Bureau of Mineral Resources Observatory Group, to select the most suitable site for a seismological observatory. In view of the desirable features for such a site - a bedrock having a high seismic velocity and a bedrock at shallow depth - a site about three miles west of Alice Springs is recommended as the most suitable; the bedrock material has a velocity of 17,800 ft/s and the thickness of overburden is less than 20 ft.

A four and a half month seismic survey has been carried out in the Poole Range area of the Fitzroy Basin by C. G. G. where both the reflection and refraction methods have been tested. Reflection experiments lead to a high multiplication of geophones and shot-holes patterns. However, tests were too limited and too scattered to allow for definite conclusions regarding the best recording procedure. The refraction method has been used to provide information regarding the extension at depth of Poole Range surface anticline. The same method was used for a reconnaissance survey on the regional gravity anomaly 16 A. Besides shallow markers, two and sometimes three deep markers were followed simultaneously. The results obtained during the survey indicate that: Poole Range surface structure has no extension at depth; - Two high zones, separated by a narrow trough appear to correspond to the gravity anomaly 16 A. The eastern high zone is a wide dome with a closure of about 4,000 ft at the level of the deeper marker. The western high zone corresponds to a shelf-like area of the deeper marker. It is overlain by sedimentary formations where facies changes are suggested by rapid variations of the marker's velocities. This is the shallowest area of the survey with a 15,000 ft/ sec marker at a depth of less than 10,000 ft. Delimination of the most interesting structural locations would require the carrying out of supplementary traverses. A tentative interpretation makes the deeper marker a probable Proterozoic level with depths ranging from 15,000 feet to 30,000 feet. The two others might represent Devonian and Ordovician formations.

Several seismic surveys were made by the Bureau of Mineral Resources, Delhi Australian Petroleum Ltd, -Phillips Petroleum Company, and L. H. Smart Oil Exploration Company Ltd during the period from 1959 to 1963 between Eula and the Queensland/South Australia border area of the Eromanga Basin. This report covers the seismic work done by the Bureau of Mineral Resources in 1962 and 1963 and also incorporates the results of the work done by the private oil exploration companies. It aims at providing information on the nature and structure of the rocks underlying the Mesozoic sediments of the Eromanga Basin. The seismic results have been interpreted with reference to the geology as known from the Delhi-Santos Orientos No. 1 and Dullingari No.1 wells near the Queensland/South Australia border and the Smart Oil Orient No. 2 well on the Grey Range.

Seismic reflection studies in the Perth Basin, between the coast and the Darling Range, 30 miles north of Perth, were conducted in an attempt to derive a suitable recording technique for obtaining reflections when shooting on the Coastal Limestone formation, to investigate geological structure in the basin,and to supplement hydrological studies being madeby the Geological Survey of Western Australia. Experimental work occupying half of the survey period failed to yield a technique for obtaining seismic reflections on the Coastal Limestone, but led to reflections being obtained across the major part of the basin, Record quality with a fairly heavy technique was poor to fair in the western half of the basin off the Coastal Limestone but improved considerably to the east. A complex geological section in the west gave way to a more concordant thick synclinal section in the east, terminated at its eastern end by the Darling Fault. Of interest is an apparent anticlinal reversal of dip in beds lying deeper than 7000 ft,with the reversal axis near the centre of the major gravity 'low' of the basin.