Geophysical data release Murchison Region, WA

Release Date: 1 November 2004

Geoscience Australia (GA) announces the release of over 146 000 line km of airborne geophysical data over the Murchison region of Western Australia covering the Cue, Kirkalocka, Ninghan and Yalgoo 1:250 000 Sheet areas.

In this area of high potential for gold mineralization, the absence of extensive geological outcrop has previously hindered exploration. These new geophysical data provide explorers with high quality pre-competitive information that significantly assists the mapping of the region's geology, and which, when used in conjunction with existing complementary data, may highlight exploration targets.

Data in this release comprise magnetic, gamma-ray and elevation located data and grids from surveys flown for GA between April and August 2004 and from one private company survey flown in November 1995. The company data have been levelled with the 2004 survey data to create a combined dataset giving a continuous coverage.

The resulting magnetic, radiometric and elevation datasets have been gridded using an 80 metre cell size. The survey areas are shown in the diagram below.

Acquired in three surveys, the new data were collected at a flying height of 60 metres along lines spaced 400 metres apart. Magnetic data were sampled every 0.1 seconds (~7 metres) whilst the sampling interval of the radiometric data was 1.0 second (~70 metres). Navigation and flight path recovery information were provided by the satellite Global Positioning System (GPS). These GPS data were sampled every 1.0 second (~70 metres).

Availability of digital data

Magnetic, gamma-ray and elevation point located data and grids can be obtained from Geoscience Australia in either of two ways:

• The data can be downloaded for free using the Geophysical Archive Data Delivery System (GADDS), or
• The data may be purchased on one CD-ROM from the Sales Centre at a cost of A$99.00 (including GST; postage and packing extra)