A collection of palaeontological papers 1972 (bulletin 150)

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This Bulletin presents the results of a marine geological survey carried out by BMR in the Arafura Sea in 1969 as part of a program of regional geological reconnaissance mapping of the Australian continental shelf. It is a continuation of work in the Timor Sea and northwest shelf (van Andel, Veevers, 1967; Jones, 1968, 1970). The area surveyed is the northern Australian continental shelf between longitudes 130° and 136°E and between latitudes 8° and 12°S (Fig. 1), an area of about 240 000 km-. From 2 to 25 May the Japanese research submersible Yomiuri and its mothership, the converted deepsea tug Yamato, were made available. The major part of the survey lasted from 21 September to 6 December 1969, using the chartered oil-rig supply vessel San Pedro Sound as a platform.

No abstract available

The Australian Calibration Line (ACL) , with a total gravity interval of 3 Gal, was established during 1970 between Laiagam in Papua New Guinea and Hobart in Tasmania. During 1973 the Australian Bureau of Mineral Resources and the USSR Geodesy and Cartography Survey made joint observations along the full length of the ACL. Measurements made with eight Soviet GAG-2 gravity meters established a gravity scale for Australia to an accuracy of 2.5 parts in 105. This scale and a datum of 979 671.86 mGal for Sydney A were adopted for Australia in 1973. The Soviet scale established for the ACL appears to be within 1 part in 104 of both the IGSN71 scale established for the Western Pacific Calibration Line by absolute determinations, pendulum measurements and international gravity meter comparisons, and the scale established for the Soviet Calibration Line by OVM pendulums. The Soviet scale for the ACL defines a milligal which is 1.5 parts in 104 larger than that defined by IGSN71 values for the ACL, and 5 parts in 104 larger than the 1965 Mean Australian Milligal that was used as an Australian milligal standard between 1965 and 1973. Both of these scales are partly based on Cambridge pendulum measurements made in Australia during 1950-51. These measurements are now thought to have been incorrect in scale. LaCoste, Romberg gravity meters have been used during six surveys along the whole or part of the ACL. The LaCoste observations have been reduced using the Soviet ACL scale and the new datum for Sydney A. The most probable values for airport gravity stations, calculated from the LaCoste results, have a precision of better than 0.01 mGal and are consistent to within experimental error with values calculated from the GAG-2 results. LaCoste observations reduced using the Soviet ACL scale give more accurate values for the gravity differences of the main intra-city ties and calibration ranges along the ACL.

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