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Legacy product, no abstract available.

Legacy product, no abstract available.

Legacy product, no abstract available.

Legacy product, no abstract available.

Legacy product, no abstract available.

The mapping of the Birdsville 4-mile Sheet area and examination of water bore logs established a sequence of at least 3,000 feet of Mesozoic sediments, unconformably overlain by Tertiary rocks which have a maximum thickness of 100 feet. The Mesozoic rocks form the main aquifer and the impermeable cap in the western portion of the Great Artesian Basin. The marine shales of the Wilgunya Formation are possible source rocks for petroleum. Source rocks occur in the Lower Palaeozoic sequence to the north, in the Boulia 4-mile area. The only known reservoir rocks are the sandstones of the Lower Cretaceous Longsight Sandstone. Neither oil nor gas has been reported from any of the water bores in the area. Showings were encountered in the Bedourie Bore, 120 miles north of Birdsville, and in the Delhi Frome Santos Betoota No. 1 Well, 100 miles east of Birdsville. No important structures or economic mineral deposits are present in the area.

The Bureau of Mineral Resources conducted a seismic reflection survey of a small area near Broome, W.A., during 1954 and1955. It was part of a general investigation of the Canning Basin and was aimed at determining the distribution of sediments south of the Fenton Fault. The seismic work indicated a sedimentary thickness of at least 6000 feet, and probably as much as 10,000 feet could be expected. It also showed that the subsurface formations are probably folded and faulted

Experience has shown that Seismic Refraction Traverses can be grossly misinterpreted unless they are very carefully carried out. The Refraction Depth Probing technique developed by the Bureau is intended to measure accurately the distribution of refractors beneath any selected station. In the Bureau's method, accurate information is first obtained along a traverse half a mile to one mile in length; the steps are as follows: (1) A number of refraction depth probes are shot with different shot-point-to-geophone distances. (2) If necessary some reflection shooting is done. (3) The results are studied to assess the value of the method in solving geological or geophysical problems. (4) The most suitable technique can be adopted for the rest of the survey in the area; i.e., the refractors which are easiest to identify, and which yield the most useful structural information, can be surveyed by the most accurate and economical method.