Preview Resources Pty Ltd has interpreted and computer modelled selected anomalies in the aeromagnetic data in the Robe Trough area as a guide to structural interpretation of the total magnetic intensity data and pseudo-depth-slice data. This is a preliminary analysis of only this one aspect of the magnetic data. Further work with the data is recommended, including more comprehensive computer modelling, integrated with seismic, to map magnetic basement morphology and its influence on the overlying section, as well as performing analyses to detect possible direct indicators of hydrocarbon leakage. For the present work, 7 individual anomalies or anomaly groups were selected which lie near the seismic lines supplied by the client, and which were considered representative of anomalies available. Anomaly sources were modelled with 2.5-dimensional and 3-D polygons using a software package named POTENT. Model cross-sections were plotted on seismic depth sections provided by OCA, and the plan views of bodies were plotted on a grey scaled TMI map produced using Surfer. Supporting computer model plots are included as an appendix. There appear to be 2 main suites of magnetic anomalies in the area studied, and corresponding with these there are 2 main suites of interpreted magnetic sources. Neither of these suites coincide with the depth range of interest indicated by OCA to lie around 1000 to 1500 metres within the deeper parts of the basin. Rather, sources model shallower and deeper than this, except on the margins of the basin where the basement shallows. A suite of shallow sources with amplitude 1-5 nT has depth to top in the range 275-500 m below ground level, and these appear to be fault parallel and confined to the Eumeralla Formation. A suite of deep sources with amplitude 20-50 nT has depth to top typically occurring at approximately 3000-5000 m below ground level (or shallower near Killarney 1 and near Lucindale 1). It is inferred that these picks correspond with magnetic basement and probably with the top of igneous-metamorphic basement. There is no evidence from the modelling or inspection of the TMI data pixel maps to support the possible existence of strongly magnetic sources within a layer at some intermediate depth below the Eumeralla and within the sedimentary section. It is likely that the Eumeralla-derived fault texture (northwest-southeast) is decoupled from the dominant basement structural texture (north-south and east-west). The magnetic effects are interpreted to be caused by the deposition of magnetic minerals on or near fault planes within the Eumeralla Formation. It is suggested that study of these anomalies may provide local indications of variations in fluid migration paths, hydrocarbon leakage and seals to possible traps.