Legacy product - no abstract available

At the request of the Geological Survey of Western Australia, the Bureau of Mineral Resources, Geology and Geophysics provided geophysical staff and equipment to assist in the search for underground water supplies in certain areas of Western Australia where additional supplies are required for further development of the farming 'industry. The main objects of the survey were to test several -types of resistivity equipment and to determine their limitations and optimum working conditions, to estimate the accuracy of depth determinations to formation discontinuities, to determine, the nature of the discontinuities, and to estimate the degree of salinity of the ground water. Results show that in 75 per cent of the measurements made, errors in depth determinations were within ± 20 per cent. Although limited control data were available, it was often possible to recognize limestones, cementation zones in limestone, sands and ground-water levels, and in granite areas, the transition from weathered to fresh granite was readily recognized. Where conditions were favourable, a satisfactory correlation was obtained between resistivity values and the salt content of solutions in a formation, provided the porosity of the formation was known. Although the main object of the survey was not, the finding of new underground water supplies, this WJ.S one of the aims in the Cue area, and a location was found where conditions for a large supply of good-quality water appeared to be favourable. The resistivity meter which was used in the tests was developed by the Bureau of Mineral Resources, and operated very satisfactorily. The Megger earth tester was reliable up to electrode spacings of 100 feet. The value of future test surveys for underground water would be greatly enhanced if more comprehensive bore information were available for correlation and combination with geophysical and geological observations. Such information should include the porosity and permeability of formations, screen analyses of samples, and salt content and resistivity of bore water.

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.

This report deals with the volcanic activity at Tuluman Volcano in St .Andrew Strait, 25 miles south of Lorengau in the Admiralty group. In the first of the three papers, which constitute the report, a description is given of the activity from June 1953, when the eruption began, to the end of July-1954. Part II describes further submarine activity in October and November 1954, and the condition of the active centres at that time. In Part III a more detailed description of the eruptive activity is given and the eruption and the associated phenomena are reviewed at some length. Volcanic activity in the St. Andrew Strait has originated from at least five, separate centres, from one of which another cone has been formed by a branching-off from the main conduit. As a result, three islands, two of which have been subsequently joined, have been built up above sea level. The name Tuluman Islands is proposed for these islands, and individual cones are numbered according to the chronological order in which they have been formed. The geographical position of the Tuluman Islands and their topography are also discussed.

This report deals with geological and geophysical investigations of the George Creek Uranium Prospect, which is 80 miles by road south of Darwin, N.T. The rocks, sandstone and siltstone, which form part of the east limb of a large north-plunging syncline, belong to the George Creek Formation of Lower Proterozoic Age. The radioactive anomaly within the 3-times-background contour covers an area of 4 acres. Torbernite is found in weak shears, joints, and bedding-plane fractures at the surface. Torbernite and uranite have been intersected by diamond drill holes. The uranium mineral intersected is below ore grade. Two more diamond drill holes have been recommended; on to test for primary uranium mineral vertically below the most highly mineralised outcrop, the other to test for an extension of uranium mineral below alluvium south-west of the most highly mineralised outcrop.

A test survey was made with a Radore Equipment over three mineralised areas in Tasmanian. The investigations were made in January, 1955 for the purpose of comparing the performance of the Radore equipment with that of lower-frequency electromagnetic equipment previously used successfully over the same areas. The results show that although some very weak indications were recorded by the Radore equipment, it has not been possible to correlate these satisfactorily with the know mineralisation. Moreover, it is difficult to distinguish indications that may possibly be due to mineralisation from apparent indications that are undoubtedly due to irregularities in topography.

During a recent visit to Portland with Dr. N. Boutakoff and Mr. Spencer Jones of the Geological Survey of Victoria, samples were collected systematically at localities along Dutton Way which skirts the eastern shores of Portland Bay and along the foreshore below the station. Locality 2 on Dutton Way represents the type of Maritemo Formation and is approximately eight feet thick. These beds overlie the white deposits of the Portland Limestone and are overlain by basalt. The monument section shows portion of the Maritemo Beds and portion of the topmost unit of the Formation, the Werriko Beds. This section is also overlain by basalt and underlain by Portland Limestone.

This paper provides a Micropalaeontological examination of samples from Carnarvon Basin, Western Australia. Samples of six cores from this bore were forwarded for palaeontological examination by West Australian Petroleum Pty. Ltd. The fauna from each core, with notes on the age and correlation is provided in this paper.

This instrument has been designed in the Radiometric Laboratory of the Bureau of Mineral Resources, t o meet the needs of those uranium prospectors who wish to build Geiger counters. The circuit has been designed so that it can be adjusted with a minimum of test equipment. Indication of the count rate is provided by a ratemeter with three ranges; 0-200, 0-1,000 and 0-10,000 counts per minute. Earphones also provide an audible indication of the count rate. The following rate describes the operation of the circuit and the procedure to be adopted to adjust the voltage at various points in the circuit for correct operation. A schematic circuit diagram is also provided and several points concerned with the mechanical design of the instrument are mentioned.

Twelve rock samples from the Rough Range Structure were submitted by West Australian Petroleum Pty. Ltd. for micropalaeontological examination. The result of the examination of an earlier collection was given in Records 1955/48. Seven of the present samples came from a gully due east of Rough Range Well No.6 and five from a gully due east of Rough Range Well No.6 and five from a gully immediately south of Rough Range Well No.7. The distance between the two well sites is approximately 2 ¼ miles. A detailed description of samples from each section together with the thickness of the section is given below. The sections from each locality are arranged in descending stratigraphical sequence.