Geophysical interpretation and modelling of the Olary Domain under cover: A hidden inverted rift system

Interpretation and 2-D forward modelling of aeromagnetic datasets from the Olary Domain to the north of the outcropping Kalabity Inlier, South Australia, is consistent with a buried structural architecture characterised by isolated anticlines (also referred to as growth anticlines) bounded by steeply dipping reverse faults. The isolated anticlines are interpreted to have formed by half-graben inversion during crustal shortening associated with the ca 1600-1580 Ma Olarian Orogeny. We interpret the bounding reverse faults as reactivated high-angle normal faults, originating from a listric extensional fault architecture As shortening increased, 'break-back bypass' and 'short-cut' thrusts developed because of buttressing of the hangingwall successions against the footwall. The resulting architecture resembles a combination of a thrust-related imbricate fan and an accumulation of inverted basins. Using this structural architecture, synrift sediments proximal to interpreted normal faults were identified as prospective for sediment-hosted massive sulfide Pb-Zn-Ag mineralisation.