Legacy product - no abstract available

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Legacy product - no abstract available Never published, see Record 1965/048 instead

Benbow crater is the main residual active centre of the large ancient volcano which has formed Ambrim Island. For the eleven months preceding December 1951 it has been the source of extraordinarily intense and prolonged explosive activity. The volume of ash and scoria ejected during this period exceeds 800,000,000 cubic metres. Evidence has been found during the recent inspection of this volcano that suggests that the current phase of explosive activity has ended. The 1950-1951 eruption, possibility of future activity, and effects of the eruption, are discussed in this report.

In Portion 11, Ph. of Stockrington Diamond Drilling near an unnamed creek tributary to Surveyor Creek has disclosed coal continuously for a distance of 7,600 feet south from the northern boundary of the Portion. The seam is split and banded and the coal is inherently high in ash. Proximate analyses of the coal were carried out by the New South Wales Mines Department laboratory in Sydney. All coal ores were forwarded from the field and shale etc. bands of greater thickness than half an inch were discarded by the analysts. Stony coal or carbonaceous shale with S.G. greater than 1.6 was also rejected from the assay samples. Consequently the analyses quoted indicate a composition roughly equivalent to that which might be expected for cleaned or hand-picked coal from this area.

The purpose of a visit to the Cloncurry district, which lasted from 21st August to 30th September, 1951, was to see what aid geophysical work could give in the search for copper deposits in this field which is one of the biggest mineral fields in Australia. While the Cloncurry district in the past produced copper from many small but rich deposits, only a few exceeded 200,000 tons, and the search now is being conducted mainly with the idea of finding and developing huge but relatively low grade copper deposits with at least several hundred thousand tons, or perhaps millions of tons of copper ore containing at least 2.5 to 5 percent copper. It is possible that geophysics might help in this search, and consequently, a number of old copper mines were visited and some geophysical test traverses made. With the rather limited facilities available the tests were confined to self-potential measurements and to a few traverses with a new Atlas gravity meter, especially suitable for ore prospecting because of its lights weight and transportability and its high sensitivity and accuracy. This report gives an account of the survey and its results.

The work done in this investigation was for use in the compilation of a large scale geological map of the A.C.T. The area mapped adjoins that mapped by Flinter and McInnes (1949) and L.C. Noakes (1946). The map accompanying this report includes all of the A.C.T. south of an east-west line through Tharwa. Geological features, including the physiography, stratigraphy, and structural geology of the area, are described in this report.

An area surrounding the magnetic observatory at Toolangi was tested for uniformity of the magnetic field. The three elements measured were declination, horizontal intensity, and vertical intensity. The main tests were carried out over the period, 10th December to 21st December, 1951. Further determinations of horizontal and vertical intensity at different heights above two of the stations were made on the 7th and 9th January, 1952. The methods of observation and results of the survey are discussed in this report.

During July and August 1951, officers of the Geophysical Section of the Bureau of Mineral resources carried out an aeromagnetic survey of the East Gippsland area of Victoria, using the Bureau's D.C.3 aircraft VH-BUR. An F24 type aerial camera was used for taking vertical photographs for the purpose of plotting flight paths of the aircraft along the flight lines. The magnetic equipment consisted of a modified magnetic airborne Detector unit type AN/ASQ-1. The aircraft was flown at an altitude of one thousand feet above terrain, along parallel flight lines running in a north-south direction one mile apart. This report comprises notes on the survey. A provisional map showing contour lines of total magnetic intensity and magnetic anomalies is attached.

This report contains notes on a gravity survey of the East Gippsland area, Victoria. The accompanying gravity map shows Bouguer Anomalies over the area in East Gippsland held as Petroleum Prospecting Leases by Lakes Oil Ltd. and Austral Oil N.L. The map is compiled chiefly from the survey by Robert H. Roy Co. U.S.A. and incorporates additional work carried out by the Bureau of Mineral Resources during 1951.