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

Abstract

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.

Assessing uncertainty in the integration of aeromagnetic data and structural observations in the Deering Hills region of the Musgrave Province

“…Aeromagnetic interpretation is increasingly being applied to analyse the structural architecture and evolution of the near surface Hills et al 2003;McLean & Betts 2003;Direen et al 2005). With high-resolution data (5500 m line spacing), interpretation is possible at a scale that permits direct comparison with geological maps.…”

“…Recently arranged access to the Deering Hills ( Figure 2) permitted one such study. Constrained interpretation of regional structure can be achieved by combining structural analysis with aeromagnetic interpretation and modelling Hills et al 2003;McLean & Betts 2003;Direen et al 2005). This approach is effective because both methods can be used to determine overprinting relationships, three-dimensional architecture and kinematics, albeit at different scales and using different criteria (Betts et al 2007).…”