Martin Fairclough

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

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.