A reflection seismic survey was made in an area north and north-west of Roma, to find whether there are any domal structures associated with the known occurrences of oil and gas. The general quality of the reflections recorded was poor, and no evidence of an anticline or basement high was found at Hospital Hill or Block 1 6 where oil and gas have been previously found. No targets for drilling were found and further seismic work is not at present recommended.

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.

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.

Beach sand deposits along the Australian east coast (Gardner, 1951 a, b) have yielded a large part of the world supply of zircon and rutile since the year 1936. During 1953 the returns from the export of these minerals amounted to more than £2,000,000. In addition the black sands contain a small proportion of monazite, which is a source of cerium and of thorium, a fissionable element that may be used for the generation of atomic power. From a comparatively small beginning the mid-1930's the beach-sand industry grew rapidly during the war and early post-war years. Little was known of the distribution and reserves of the deposits; hence the Bureau of :Mineral Resources undertook a detailed investigation of the coastal area between Southport, Queensland, and Woody Head a little north of the mouth of the Clarence River, New South Wales. The primary object of the survey was to determine the reserves of monazite and therefore of thorium; the reserves of zircon, rutile, and ilmenite were also determined. In this report the source rocks of the sand and heavy minerals are considered in a brief outline of the physiography and general geology of the country between the coast and the main divide. The deposits are described and their origin and distribution discussed in connexion with late Pleistocene and recent changes, in sea level. The reserves and distribution of the heavy minerals arc broadly summarised, and more details of reserves and dimensions of deposits and overburden are given in descriptions of the individual areas.

In July, 1949, the Bureau of Mineral Resources, Geology and Geophysics began an investigation of the geology and mineral resources of the Harts Range Region, Central Australia, an area of about 2,000 square miles between Latitudes 23° 00' south and 23° 30' south, and Longitudes 12:3° 45' east and 135° 30' east. The undertaking was prompted by the discovery of small amounts of radioactive minerals in pegmatites in the eastern portion of the range. It was soon realized that the deposits of radioactive minerals were not of economic size, and the investigation was therefore extended to other mineral deposits, and in particular to the mica deposits of the Harts Range and Plenty River.he Harts Range and Plenty River Mica Field is the most. Important in Australia, and had yielded 859.49 tons of commercial muscovite .valued at £692,794 to the end of 1952. The investigation of the field was carried out in field seasons between July, 1949, and October, 1951. The mica-bearing pegmatites occur in the rocks of the Harts Range Group, a complex of metamorphosed igneous and sedimentary rocks probably of Archaeozoic age.

Legacy product - no abstract available

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