Geophysical modelling of the Gawler Craton, SA - interpreting geophysics with geology

Abstract

Geophysical ?worming? was applied to potential field data over the Gawler Craton. ?Worming? is a multi-scale edge analysis technique that can aid in identifying structural controls and depth to anomalies. A geological interpretation of the worming 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 ?worming? 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 which may be present (for example, is a structure really likely to be associated with mantle-tapping fluids?). 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 U-mineralisation in IOCG systems in the Gawler Craton may be dependent on the interconnectivity of fault plumbing in three dimensions to nearby uraniferous Mesoproterozoic granitoids.