Legacy product - no abstract available

Rurnbalara railway siding is 831 miles by rail north of Adelaide, South Australia, and 120 miles by rail south of Alice Springs, Northern Territory. The ochre deposits (Plate 1) are situated in desert country, 15-20 miles northeast of the siding. No permanent water supply has been developed in the vicinity of the mines. Numerous mesas in the district are capped by siliceous laterite (grey billy), and are composed of approximately 150 feet of horizontally-bedded, leached shales and sandstone containing numerous fossils of Lower Cretaceous age. These beds, for which the name Rumbalara Shale is proposed, rest unconformably on the eroded surface of flat-lying, current-bedded sandstones of which the age has not been determined; it is proposed that the sandstone beds be called the De Souza Sandstone. .The ochre occurs in beds 1 to 4 feet thick; the best grade consists of soft, friable, golden-yellow material, free from grit and with good paint-making properties. Throughout the deposits the ochre occurs at the same stratigraphic horizon- at the base of the Lower Cretaceous-and appears to be of sedimentary origin. Excluding 1943 and 1944, annual production during 1940-1948 averaged 500 tons; in 1943 and 1944 production was 1,345 and 1,439 tons respectively. The deposits are very extensive, but prospecting carried out to date indicates that only some of them contain ochre equal in grade to that being mined. However, although there are virtually no proved reserves, the field is probably capable of supplying Australia's requirements of yellow ochre for many years.

No abstract available

This report covers the results of a seismic reflection traverse on a portion of the Giralia anticline which has been mapped in Mesozoic and Tertiary rocks in the North-West basin. The work constitutes a part of a general programme of investigation which the Bureau of Mineral Resources, Geology and Geophysics, has been carrying out on Permit areas held by Ampol Petroleum Ltd. in this area. The seismic traverse described herein lies along the main road joining Giralia and Bullara homesteads and crosses the northern end of the Giralia structure. Tests were made with shooting in shot holes and also by air shooting. In addition, a refraction spread was shot along the axis of the anticline. This report gives an account of this investigation. Technical matters, such as interpretation technique and the symbols used in plotting results, are briefly noted. The results of the study and subsequent conclusions are discussed.

As a result of abnormal rains in 1950, a considerable body of water has been impounded in Lake George, situated in New South Wales, but only 20 miles north of Canberra, Australian Capital Territory. Local reports claim a depth of water of 30 feet in the Lake and these reports have prompted the Advisory Council of the Australian Capital Territory to investigate the possibility of developing the lake as a recreational resort. As a first step in this investigation the Council has asked the Bureau of Mineral Resources, Geology and Geophysics for an opinion as to how long a considerable body of water may be retained in the lake.

The Government of India invited the Australian Government to send a representative to the celebration of the Centenary of the Geological Survey of India during January 1951. The first meeting of the Pan-Indian Ocean Science Congress was scheduled for the first week in January, 1951 so the Bureau of Mineral Resources, Geology and Geophysics selected M.A. Condon to attend the Science Congress and the Centenary Celebrations because his work in the North-West Basin of Western Australia would be of some interest to geologists working around the Indian Ocean. This report comprises a detailed itinerary and geological notes on the areas visited during the course of the visit.

A small collection of rock samples containing Gondwana type fossil plants from three localities near Collinsville is discussed in this report. All assemblages - although with some conspicuous differences - show the characteristic Permian Glossopteris Flora. On the determination of the representatives of this flora alone, however, it cannot be said to which particular horizon within the Permian Bowen Series the samples from Collinsville belong. Modern statistical methods are suggested.

The Ordovician age of the limestone at the Belubula River was recognized by the present writer from fossils collected by Mr. N.C. Stevens, University of Sydney. Thought, in the opinion of A.A. Opik, the first collection examined was completely convincing, Mr. Stevens approached the Chief Geologist, Dr. N.H. Fisher, early in 1951 for further support in the field. It was then decided that A.A. Opik, being responsible for the age-determination of the fossils from the Belubula River, Cliefden Caves area, would accompany Mr. Stevens on a field excursion to collect more evidence for the age of the limestones and to look for an occurrence of Silurian fossils in the same area. The results of this examination are given in this report, comprising a description of the Ordovician sequence, and a summary of the stratigraphy and correlation of the Ordovician Belubula River.

A seismic survey was carried out near Roma during 1949-50, being part of a geophysical programme to search for structures likely to be significant for oil exploration. As preparation and publication of the final report on the survey may take some time it is desired to present briefly the main results in the form of a preliminary report. The first phase of the geophysical survey work at Roma comprised gravity and magnetic surveys, the results of which were presented in Bulletin No. 18. The residual gravity pattern revealed two possible structural high closures. The object of the seismic surveys was to prove or disprove the existence of these structures, and to obtain more detail concerning them if proved.

This report contains the results of brief geological investigations carried out in conjunction with the Land Research and Regional Survey Unit to provide information on land types and their distribution in the Burdekin River Valley. A geological map and sections at the horizontal scale of 4 miles to 1 inch have been compiled from air-photo interpretation controlled by widely spaced land traverses. An account of the stratigraphy is given, and palaeontological reports on the fossils collected appear as appendices.