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  • Between February and April 1961 the Bureau of Mineral Resources, Geology and Geophysics made a seismic survey in the Rosedale area of the Latrobe Valley, partly at the request of the State Electricity Commission of Victoria to provide more information about the brown coal measures in this area, and partly in order to test the Bureau's latest seismic recording equipment. One traverse, combining both reflection and refraction profiling techniques, was run south from the A.P.M. No.1 bore at Rosedale as far as Merrimans Creek, and a second traverse was run west from the bore as far as Toongabbie. Results show that the maximum thickness of the Tertiary sequence is about 3000 ft and that it thins gradually to 1000 ft at Toongabbie and rapidly to about 750 ft on the Baragwanath Anticline. It is shown that early Tertiary deposits were laid over the whole area but have been uplifted and partly eroded in late Tertiary or post-Tertiary times in the Toongabbie and Baragwanath areas, but the main syncline sank and accumulated thick Tertiary sediments. Results show alao that on the northern flank of the Baragwanath Anticline where crossed by the seismic lines the Tertiary and Jurassic sediments are steeply folded but not necessarily faulted. No positive information was obtained below 4500 ft but long refraction shots suggest that a high-velocity basement does not exist at a depth less than 12,000 ft.

  • The seismic survey extending over the Poole Range and Price's Creek areas and the Pinnacle Fault, near the north-eastern boundary of the Fitzroy Basin. The survey was corducted during the winter of 1953. The Poole Range Dome has been mapped in outcropping rocks of Permian age, but its western closure is notcertain. It is at the south-eastern end of a line of anticlinal folding which includes the St. George Range Dome and Nerrima Dome. The target beds for an oil test bore would be the Devonian and/or Ordovician rocks, which crop out on tbe north-eastern side of the Pinracle Fault, ard over which the Permian rocks of the Poole Range are believed to lie unconformably. The seismic results indicate a thick section of sediments on the south-western side of the Pinnacle Fault and show a fair defree of conformity between shallow and deep reflections on the northern flank of the dome. Further investigation was made in 1954 around the flanks of the dome, to determine whether or not the domal structure persists at depth, but the interpretation of the results of the 1954 survey is not yet complete. The Ordovician roeks on tbe northeastern side of the Pinnacle fault are shown to have a probable unexposed thickness of about 900 feet.

  • Presentation delivered at the Tasman Frontier Workshop, 89- March 2012

  • The Bureau of Mineral Resources made three seismic surveys in the Ngalia Basin, Northern Territory, during 1967 to 1969 as part of a comprehensive geological and geophysical investigation of the structure and stratigraphy of the basin. L079 is the first survey done in 1967. The project was aimed at delineating the configuration of the basin, within which outcrops are sparse, and providing information pertaining to its depositional and tectonic history. Investigation of the extent of Lower Palaeozoic sedimentation was considered to be important in assessment of the petroleum prospects of the basin. Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 75658

  • The Bureau of Mineral Resources'No. 2 seismic party conducted a Survey over the Palm Valley Anticline 80 miles west of Alice Springs, from 2nd November to 22nd November 1961. The seismic reflection method showed (a) the anticlinal structure existed at depth and (b) at the northern end of the main north-south traverse in the Missionary Plains north-dipping reflections were recorded from about 2500-ft depth. A shallow refractor was recorded in which the velocity Was 17,800 ft/sec. This refractor, which could not be positively identified, prevented, any useful deeper refraction information being recorded.

  • At the request of West Australian Petroleum Pty. Ltd. and the Department of Mines, Western Australia, the Bureau carried out a seismic velocity survey in Rough Range No.1 Well, with the object of obtaining velocity distribution data for use in the interpretation of results of seismic refraction surveys in the area. Twenty-two shots were fired from a shot point about 1,000 feet from the well. Geophone depths in the welI ranged from 2,000 feet to 14,000 feet, usually at intervals of 500 feet, but the intervals were varied at points where there was a significant change in the stratigraphy. Recordings from 16 of the shots were used in the calculations. Results indicated that, as would be expected, the hard crystalline limestone which comprises the top 700 feet of section has a much higher velocity than the clastic limestones which underlie it. An abrupt velocity change from 7,100 ft/sec. to 12,600 ft/sec. at 3,250 feet corresponds approximately with the change from Windalia Radiolarite to Muderong shale, and also with a density change from 2.1 to 2.4. A second major velocity change from 12,600 ft/sec. to 16,500 ft/sec. at 6,800 feet also corresponds approximately with a density change from 2.5 to 2.7. An abnormal increase in velocity recorded at about 9,000 feet must be considered as very doubtful and velocities at this depth have been averaged.

  • During 1969, the Mundaring Geophysical Observatory collected seismic refraction data from explosions used by the Bureau of Mineral Resources No. 2 seismic party in the southwest of Western Australia. The seismic party exploded 37 charges up to 4,500 kilograms on a traverse from Balladonia through Kalgoorlie to Perth. Two mobile Willmore seismographs and permanent seismographs at Mundaring and Kalgoorlie recorded the resultant seismic waves. Raw data for this survey are available on request from clientservices@ga.gov.au - Quote eCat# 76503

  • Seismic reflection traverses were surveyed across the Perth Basin at Cookernup, W.A. These traverses were planned to find the thickness and dip of the Basin sediments adjacent to the Darling Scarp and to discover any faulting or folding within them; also to determine the applicability of the seismic method as a tool for both regional and detailed investigation in this area. Seismic refraction traverses were surveyed to help in the solution of problems encountered in the interpretation of the reflection cross-sections. The survey indicated a considerable thickness of sediments about 20,000 ft, at the eastern margin of the Basin near the Darling Scarp, and suggested tectonic structure that is not indicated in surface geology, The reflection traverses indicated that sediments (presumably Lower Palaeozoic or Precambrian) lying deep in the Perth Basin may continue underneath the Darling Scarp and abut the granitic gneisses etc. of the Western Australian Shield on an overthrust fault plane. The overthrust fault, if it exists, does not reach the surface, but is covered to a depth of possibly some few hundred feet by younger sediments and also by alluvium eroded from the Darling Scarp. Some reflection and refraction shooting was done in an attempt to test this and other hypotheses, but the results crc inconclusive. Gravity results strongly suggest a normal fault, and if normal faulting is the case, the reflections from beneath the outcropping basement are possibly derived from shear zones, Some probable 'reflected refractions' were also observed. There is scope for further seismic testing but it is considered that conclusive evidence could only be provided by drilling.

  • Near surface information can be obtained from regional seismic data showing the weathering and layering properties, as well as dipping bedrock structures. Hard limestone layers in the near surface overlying soft sediments make complex refracted arrivals and refraction statics are difficult to define and in some cases it is best not to apply refraction statics to the reflection data. For some of the data in this survey surface sand dunes over 10 m high caused significant time delays for reflected data and refraction statics were essential prior to further reflection processing. Numerous refraction models were produced and tested along the data. Refraction models provided useful information about layering in the near surface, and helped with the seismic processing. The refractor models also indicated the possible presence of ground water. In some places the refracted arrivals changed polarity indicating either change in thickness or hardness of the limestone at the near surface overlying slower unconsolidated sediments. These regions sometimes correlated with diminished reflections. Dip moveout (DMO) correction was essential to improve near surface steep dipping structures.

  • Details and results are given of a seismic refraction survey made at the request of the Hydro-Electric Commission of Tasmania, to investigate the proposed site for a power station with penstock lines and tail race. The power station is part of the Wayatinah "A" project. The object of the survey was to determine the thickness of the alluvial gravel formation on the river flat, the weathered section of the sandstone and the dolerite, and to indicate the presence of shear zones. Three traverses parallel to the proposed penstock line, and 100 feet apart, and three cross traverses were surveyed in January and February, 1954. After completion of the original survey two additional traverses were surveyed on the location chosen for the power station, penstock lines and tail race site.