Role of geophysical methods applied to mapping mineral systems under the Murray Basin cover

Abstract

This paper reviews the role that geophysical methods have played in mapping mineral systems beneath Murray Basin cover in the Stawell corridor of western Victoria. North of Stawell, the Stawell corridor has been shown to extend more than 100 km to the north-northwest, beneath increasing thicknesses of Murray Basin sediments. Based on a geological model developed at Stawell, geophysical methods have played an essential role in mapping new mineral systems in the belt beneath this cover. Regional geophysical data (principally magnetics and gravity) supplied by GeoScience Victoria have been supplemented by company surveys for more detail in selected areas. In addition, various electrical methods have been tested for direct detection of mineralisation beneath deep conductive cover. The results have led to the detection of several mineralised systems many kilometres from outcrop and with no surface expression. Petrophysical measurements on core samples and geophysical logging of drillholes have been essential to the interpretation of geophysical data, and they have also contributed to further understanding of the mineralising processes.

Key words:

• electromagnetics
• geophysics
• gravity
• induced polarisation
• magnetics
• magnetotellurics
• petrophysics
• Stawell

Acknowledgements

The support and encouragement of the management of pmd * CRC, Stawell Gold Mines and Leviathan Resources is acknowledged. Without such a visionary management, this exploration program would not have proceeded, and the successes that have been achieved would not have occurred. Permission to publish these results is appreciated.