AusMT / surveys / Western South Australia Array

Western South Australia Array GDS

Geomagnetic depth sounding survey · South Australia · Flinders University

Part of the Australia legacy GDS collection

Twenty-seven magnetometer stations fill a box some 590 km by 640 km across western South Australia, from Nullarbor homestead and Ceduna on the Bight coast north across the western Gawler Craton towards the Coober Pedy district, between 130.

About this survey

Twenty-seven magnetometer stations fill a box some 590 km by 640 km across western South Australia, from Nullarbor homestead and Ceduna on the Bight coast north across the western Gawler Craton towards the Coober Pedy district, between 130.9 and 137.02 degrees east and 27.3 and 33.1 degrees south, at a near-uniform spacing of 66 to 122 km. A twenty-eighth station, FUV, is recorded at exactly 35.00 south, 137.00 east, in Investigator Strait 250 km from the rest, and reads as a base site whose coordinate was rounded to whole degrees. No full station names survive, only the three-letter codes; Nullarbor, Ceduna and Watson are matched to the coordinates from the gazetteer, and Poochera, Maralinga and Oakden Hills are weak guesses. The array is known only from the Australian Electromagnetic Database, the register of Australian induction arrows compiled by Liejun Wang at the Australian National University, and no operator, publication or acquisition date for it has been found. Comparison with published station maps shows the array is distinct from the better documented western South Australian experiments. None of its stations coincides with the twenty-eight of the coast-effect profiles Antony White and O. W. Polatajko ran between 1975 and early 1978, the seven-station Robe to Mildura profile of 1976 lies 700 km to the east, Constable's 1983 South Australian Electrical Sounding Project made its electrical soundings east of 138 degrees 20 minutes, the 1989 marine transect off Robe does not fall in this footprint, and A. P. Hitchman's only work inside the box is three offshore floats of April 1998, not a land array. Constable's 1983 inventory of Australian array studies covers no part of the footprint, so on AusMT's reading of that figure the array is later than 1983, and Wang had not catalogued it by 1998. Its transfer functions carry the same seventeen analysis periods and the same standard errors as the AWAGS array of 1989 - 90 and the Skippy-3 array of 1994, which on AusMT's reading places its processing in the fluxgate cohort of Francois Chamalaun's era rather than the 1970s. In 1978 White and Polatajko proposed a magnetometer profile across the Gawler Block on the west coast of South Australia, to reproduce the shield curve of J. E. Everett and R. D. Hyndman. Their proposal was for a profile, not an array of this shape, and nothing on record connects it to these stations.

For all twenty-eight stations the register holds transfer functions at seventeen periods from 389 to 27,307 s, each with a standard error on magnitude and direction. The arrows themselves show a clean southern-margin coast effect, strong and pointing south-west to south towards the Great Australian Bight along the southern and western half of the array and decaying to small, scattered arrows across the northern interior (AusMT's reading of the register).

The served numbers are vertical magnetic field transfer functions, induction arrows at seventeen periods from 389 to 27,307 s for twenty-eight stations. They come from reference code 11 of Liejun Wang's Australian Electromagnetic Database, station records 309 to 336 with their 476 arrow records, and every value carries the register's own one standard error on magnitude and direction, which travels through to the served files. The coordinates are the register's own, since no published position for this array has been found, and FUV's are the whole degrees the register prints. How those records entered the register, and from whose field work, is not recorded, and the original recordings are not held.

Data and downloads

Stations (28)

Contributors and organisations

Organisation

Flinders University

Licence

CC BY 4.0

Identifiers and provenance

Machine-readable survey record · catalogue schema mtcat 2.0