The R502 series of maps has been replaced by the National Topographic Map Series (NTMS). The R502 series consists of 542 map sheets and covers Australia at a scale of 1:250,000. It was compiled from aerial photography, but only about one quarter of the series was contoured. The standard sheet size is 1 degree of latitude by 1.5 degrees of longitude. Transverse Mercator map projection and Clark 1858 datum were used. Coverage of the country was completed in 1968.

During 1950-51 pendulum gravity observations were made at 59 stations throughout Australia using invar pendulums on loan from the Department of Geodesy at Cambridge University. A national gravity base station was established at Melbourne. Subsequent comparisons with gravity meter ties suggest that the pendulum value is about 2 mgal. low. The standard errors of the gravity differences from Melbourne to the other stations have been estimated from internal consistency of the pendulum observations and from comparison with gravity meter measurements; the mean standard error is about 0.6 mgal. A small systematic difference from gravity meter values is assumed to be caused by the effect of the earth's magnetic field on the pendulums; after correction for this, the results agree fairly well with the American calibration system. Free air, Bouguer and isostatic anomalies have been calculated for all stations. The isostatic anomalies are for both Airy-Heiskanen and Pratt-Hayford hypotheses, and for four different assumed crustal thicknesses in each case. The isostatic and Bouguer anomalies are predominantly negative. A degree of isostatic compensation is present, but some large anomalous areas are uncompensated. The pendulum survey forms a basic network to which past and future gravity surveys can be referred.

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

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

This Record consists of a collection of reports completed by the petrographic and mineragraphic section of the Geological Laboratory during the period October to December, 1957.

This report covers gravity survey work conducted by Mines Administration Pty. Limited for Associated Freney Oil Fields N. L. during the period 20th June to 31st July 1959. The survey was conducted in conjunction with the seismic survey carried out by the Bureau of Mineral Resources. The purpose of the work was to define at depth the limits of the Cooroorah Anticline, Central Queensland. Gravity values were observed and plotted over the whole of the Cooroorah area, and, in particular, over the Cooroorah Anticline. These values indicate a broad gravity '''low'' south of the Mackenzie River and west of Bluff. This is confirmed by the previous regional gravity survey of 1958. Over the Big Churchyard Culmination of the Cooroorah Anticline the gravity gradient reverses. The axis of this reversal is displaced approximately 1 1/4 miles north-west from the axis of the Cooroorah Anticline. The seismic survey shows that the structure at depth is closely conformable with the surface structure so it appears from this displacement of gravity and geological axes that the gravity "high" is due to some deep-seated density variation.

The Irrigation and Water Supply Commission is searching for underground water, at the 54.5M Albert River alluvial flats site, near Beaudesert, Queensland. At their request a seismic refraction survey was conducted by the Bureau of Mineral Resources to search for suspected subsurface river channels with aquifers. This Record gives a description of the survey and its results. It was possible to identify the water table by the seismic refraction method. The deepest places in the bedrock profile interpreted as possible locations of subsurface river channels were indicated at the following positions : between X26 and X30, X5, X7, between A7 and A8, and between C17 and 018.

A reflection seismic survey was conducted in 1959-60 on Authority to Prospect 55P by Austral Geo Prospectors Pty. Ltd. for Associated Australian Oilfields N. L. through their management affiliate, Mines Administration Pty. Ltd., in an area approximately 30 miles north of Roma, Queensland. The primary purpose of the survey was to determine whether the sedimentary section thickened northward into a geologic basin postulated to exist north of the Roma area. A secondary objective was to outline any structure that might be disclosed by the initial lines of survey. Data obtained show a rapid thickening of section towards the north and east of the junction of Eumamurrin and Bungil Creeks. A pronounced structure was outlined in the vicinity of land portion 8, Parish of Eumamurrin and land portions 43V and 55V, Parish of Gubberamunda.

This report covers gravity survey work conducted by Century Geophysical Corporation for Magellan Petroleum Corporation during the period 1st July to 31st December 1959. The survey was made following an aeromagnetic survey. The gravity survey was intended to corroborate the magnetic interpretation; to provide further information as regards depth to basement and fault systems; and to indicate structural "highs" which could then be more precisely delineated by seismic reflection methods. Gravity values were observed and plotted over the area surrounding Winton, Queensland. Both the gravity survey and the aeromagnetic survey indicate a fault or fault zone across the area. In an appendix by the Bureau of Mineral Resources, it is stated that a seismic profile crossing this zone indicates that this zone is either a fault or a monoclinal fold. Magellan Petroleum Corporation are planning to deepen the water bore at Corfield, and if this does not provide sufficient information regarding the deeper rocks, a further stratigraphic test will be drilled at Winton.

This report outlines the results of a palynological study of core samples and the deepest cuttings from the Penola No.1 well, South Australia