Legacy product - no abstract available

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Legacy product - no abstract available

The core sample of grey marl was collected from the No. 2 Bore, Parish of Glencoe South, and came from the depth of 110-125 feet. The results of a micropalaeontological examination of the sample are described in this report. The species of foraminifera recognised in the sample are listed.

During an inspection of limestone deposits at White Rocks on 2/11/50, samples of weathered granite were collected from a quarry on the eastern side of the Queanbeyan-Cooma road, about 150 yards south of the two-mile peg. This quarry is in the Queanbeyan Clay Deposit described by W.G. Woolnough in departmental reports dated 17/2/28 and 20/6/28. If the rock can be economically crushed and worked, it may be suitable for the production of sewer-pipes and other impervious ware. The samples, reserves, and suitable uses for the granite are described in this report.

The main sedimentary basins of Western Australia are arranged peripherally to the pre-Cambrian shield which forms the greater part of the state. In 1948, the Commonwealth Bureau of Mineral Resources, Geology and Geophysics, by arrangement with the government of Western Australia, commenced detailed geological reconnaissance of the Fitzroy and North-West Basins. In 1948 and 1949, the R.A.A.F. carried out a programme of aerial photography of these basins and this air-photo survey has since been used as the basis for mapping in the field. In the course of this work several discoveries have been made and as only brief mention of them has been made elsewhere they are included in this summary. The main areas of Palaeozoic sedimentation in Western Australia at present known are the Ord Basin in the far north-east, the Fitzroy Basin, the North-West Basin stretching from Onslow to the Murchison River, and the Irwin-Perth Basin stretching from Geraldton to Busselton.

The areas included in the geophysical survey, namely the Laloki, Moresby-King and Dubuna leases, are among those held by Mandated Alluvials N.L., and lie in the Astrolabe Mineral Field. The positions of the leases held by the Company are shown in Plate G73-1. Laloki, the main producer of copper, is situated 20 miles by road from Port Moresby, near the junction of Sapphire Creek with the Laloki River. The Bureau was requested by Mandated Alluvials to carry out a geophysical survey in the vicinity of the known deposits and in adjacent areas. Both Laloki and Moresby-King mines has been in production up to the time when the war in New Guinea caused a suspension of operations. During the war the mine workings and much of the plant were completely destroyed. When consideration was given to the best method of reopening the mines it was decided that, if a large enough tonnage or ore could be proved sufficiently close to the surface, it would be most profitable to continue open-cut mining, and possibly install a flotation concentrator to avoid the troubles that had always accompanied smelting. The aim of the geophysical survey was, therefore, to locate a body of ore large enough to justify the adoption of these mining and treatment methods.

Mapping carried out at Kuridala by C.J. Sullivan and R.S. Matheson during the period June 17th-27th has shown that the ore deposits occur in a major fault (and associated lesser shears). The existence of the fault system is considered to have been proved, and it has been traced, with some interruptions over a distance of three miles. It may extend for many miles beyond the present limits of mapping. The geological information given appears to rule out a number of chances of occurrence at shallow depth, formerly considered likely, and thus is somewhat discouraging. However, the work does indicate that repetition deposits are likely to be present and opens up intriguing possibilities.

The area investigated, now commonly known as the Daly River Area, is situated on the north-eastern bank of the river, about 35 miles from the river mouth, and approximately 80 miles south of Darwin. The present survey was made in July 1950, in conjunction with work being done by the Bureau at Rum Jungle, and was a general investigation for possible radioactivity in the district. Although no radioactivity of interest was detected, it is considered desirable that the results of the investigation should be recorded. The geology of the area, field work, and results are described in this report.

The samples described in this report, which were submitted by the Director for petrographical examination, come from the Janjukian and Anglesean deposits between Torquay and Airey's Inlet. All sedimentary rocks from the area have been named according to the classification drawn up by M.A. Condon. The results of a rough chemical analysis made in 1947 on a sample of supposed jarosite are given, and a note on the occurrence and possible origin of the glauconite found in many of the samples is appended.