SADME stratigraphic drilling, which was undertaken recently based on detailed geophysical modelling of aeromagnetic data, has identified the major linear aeromagnetic anomaly associated with the Karari Fault Zone (NW Gawler Craton) as a major (300 km strike length), subvertical, Early Proterozoic, intracratonic, mylonitic shear zone, separating quartz + sapphirine bearing granulites to the NW from upper amphibolite facies gneisses to the SE. The aeromagnetic anomaly is produced by interlayered magnetite rich (iron formation) metasediments, semipelitic metasediments and thin pegmatites. Kinematic indicators, including asymmetric megacryst tails, elongation lineations, vergence relationships of S-C foliations, and mica fish, indicate subvertical to steeply southwards - directed downthrow of the NW block with a sinistral strike - slip component. The shear zone represents a major zone of crustal weakness which has remained active until the Tertiary. An earlier, possibly Archaean, movement history along the zone, with upthrusting of the NW block, is suggested.