Geophysical modelling of the Gawler Province, SA – interpreting geophysics with geology*

Philip Heath; Tania Dhu; Gary Reed; Martin Fairclough

doi:10.1071/EG09030

RESEARCH ARTICLE

Previous Contents Vol 40(4)

Geophysical modelling of the Gawler Province, SA – interpreting geophysics with geology^*

Philip Heath ¹ ² Tania Dhu ¹ Gary Reed ¹ Martin Fairclough ¹

+ Author Affiliations

- Author Affiliations

¹ Primary Industries and Resources, South Australia, PO Box 1671, Adelaide, SA 5001, Australia.

² Corresponding author. Email: philip.heath@sa.gov.au

Exploration Geophysics 40(4) 342-351 https://doi.org/10.1071/EG09030
Submitted: 11 June 2009 Accepted: 15 October 2009 Published: 7 December 2009

Abstract

Multi-scale edge detection was applied to potential field data over the Gawler Province in the central part of South Australia. Also known as worming, the multi-scale edge analysis technique can aid identification of structural controls and depth extents of anomalies. A geological interpretation of the multi-scale edge detection results was then undertaken; integrating drill-hole information, ground mapping and tectonic understanding with geophysical modelling to gain a better comprehension of the dominant structures present.

The multi-scale edge detection process provides potential solutions for the lack of outcrop, particularly that which is representative of three-dimensional architecture. The latter is particularly important in understanding how terrains are juxtaposed or dissected tectonically which, in turn, influences the style of any mineral system that may be present. Moreover, correct identification of structural geometry and cross-cutting relationships allows a more confident assessment of fault kinematics and potential dilatancy. In particular, the degree of uranium mineralisation in iron-oxide-copper-gold systems in the Gawler Province may be dependent on the interconnectivity of fault plumbing in three dimensions to nearby uraniferous Mesoproterozoic granitoids.

Key words: Gawler Province, multi-scale edge detection, worming.

Acknowledgements

The authors acknowledge Stephen Petrie for his contribution with the reduction to the pole of the state TMI grid and advice on map presentation. Also, we thank Anthony Reid and Wolfgang Preiss for helpful comments and suggestions relating to the geological interpretation. This work would not have been possible without GIS help from Laszlo Katona and George Gouthas. We also acknowledge Peter Milligan for his help with identifying problems early in the processing stages of this work. Finally, thanks to Des Fitzgerald from Intrepid Geophysics for providing worming software.

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| Crossref | GoogleScholarGoogle Scholar | Dhu T. , Reed G. , Cowley W. , and Fairclough M. , 2009, Mapping depth to crystalline basement in South Australia: ASEG-PESA Adelaide 2009, Primary Industries and Resources South Australia.

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^* ^*Presented at the 20th ASEG Geophysical Conference and Exhibition, February 2009.