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

40% east F55/B1-36 Contour interval: 10

Several species of Aconeceratinae occur in the Windalia Radiolarite (Upper Aptian) of the Carnarvon Basin of Western Australia. Two of them belong to the genus Aconeceras Hyatt, the third is made the type species of Eofalciferella nov., which is believed to be the ancestor of Falciferella Casey. Two new species of the latter genus have been discovered in the Upper Albian of northern South Australia. This is the first record of the genus outside England. Since Whitehouse (1926b, 1927, 1928) revised the then known Cretaceous species of Eastern Australia very little has been added to our knowledge about Australian Cretaceous ammonites. Spath (1926, 1940) first recorded the occurrence of Senonian and Maastrichtian ammonoid faunas in Western Australia. The important late Albian and Cenomanian assemblages of Northern Australia (Darwin, Bathurst and Melville Islands) are still only sketchily known (Etheridge fil. 1902, 1904, 1907) and are in need of revision, as has become evident from recent bed-for-bed collecting carried out in this area by Dr. B. Daily, of Adelaide. A monograph on this magnificent assemblage will shortly be published by Dr. C. W. Wright. An Upper Albian ammonoid fauna, collected by Dr. H. Wopfner, A. Hess, D. Scott and the author (all of Geosurveys of Australia Ltd., Adelaide), has recently been dispatched to Or. R. A. Reyment (Stockholm) for description. The Aptian/Albian, Senonian, and early Maastrichtian faunas of Western Australia are being described by the writer and the first two parts (Neoammonoidea Irregularia) will appear under the auspices of the Commonwealth Bureau of Mineral Resources, Canberra.

An experimental seismic survey was conducted at Haddon Downs, South Australia, during Octobor and November.1957. The area lies within the Eromanga Sub-basin of the Great Artesian Basin, and at least 5,500 feet of Mesozoic section are known to exist there, part of which is of a marine facies. Preliminary reconnaissance work by geologists of Santos Ltd. which holds an Oil Prospecting Licence over the area, revealed some large anticlines on the surface. The Company has already completed a limited amount of gravity work which gives promise of supplying useful information on both regional and detailed subsurface structure. Two important refractors were recorded which may be useful for semi-regional mapping. A refractor of velocity 10,250 ft/sec. was recorded from a depth of about 2,700 feet, and this may represent the top of the marine Cretaceous section. The second refractor of velocity 17,000 ft/sec. and aidoroximate depth 7,250 feet may be just below the base of the Mesozoic section. Large multiple geophone arrays and pattern shots were needed to obtain good quality reflections over most of the area, except when shooting on the alluvial plains of the larger creeks. The sedimentary section was shown to be at least 8,000 feet and possibly 16,000 feet thick, The base of the Mesozoic section is interpreted as being 7,250 feet deep on the refraction traverse and 8,600 feet at the south-east end of the reflecta.on traverse. The rest of the section probably consists of Palaeozoic sediments. If so, the high velocity (17,000 ft/sec.) suggests that a dense elastic or crystalline limestone is probably present near the top of them. The structure of the Mesozoic section is subhorizontal, but there may be minor structures with dips less than 1 degree which correlate with the surface structures.

An experimental seismic survey was conducted at Surat, Queensland, on behalf of the Australisa Oil and Gas Corporation Limited during a five week period from May 28th to July 2nd. 1958. The area lies within the southeastern portion of the Great Artesian. Basin on Authority to Prospect No. 36P and, sel the evidence of numerous bores near Roma, and a few other scattered bore logs, is considered to contain sediments suitable for the generation and accumulation of hydrocarbons in possible, economic vantities. A local geological survey by the Australian Oil & Gas Corporation suggested a structure of considerable dimensions - the 'Weribone Uplift' - which, if substantiated, would provide a promising location for a stratigraphic test bore. The experimental survey conducted by the Bureaushowed that useful results could be obtained throughout the area by conventional methods of reflection and refraction shooting. The reflection shooting indicated a fairly uniform sedimentary section with generally flat-lying beds and a probable total thickness of 7,000 to 8,000 feet. The refraction work recorded several velocities: including one near 19,000 f/s which is assumed to be a basement velocity. Depths measured to this high Velocity refractor support the estimate of the thickness of sediments made from the reflection cross-section and indicate 4 south component of dip of about 40 ft. per mile across the area surveyed. Neither the reflection nor the refraction work gave any evidence for the existence of the 'Weribone Uplift'. However, the more northerly refraction traverse indicated a local component of north dip at basement depth, and a single reflection record shot along that traverse suggested a substantial thickening of the deeper sediments towards the north. Insufficient seismic work was done to estimate the northwards extent of this dip. Such limited evidence might well indicate a purely local irregularity in basement topography. On the other hand, the north dip could be extensive, and therefore structurally significant. Any further seismic work contemplated in this area should be directed, in the first instance, towards checking this possibility.

These documents have been scanned by the GA Library. Please refer to the document for contents.