Several potential diatreme-like circular targets up to 1 km in diameter were identified from an interpretation of regional and subsequently acquired infill aeromagnetic data over an area of the north-western Gawler Craton, 55 km south of Ooldea Siding on the Trans Australian Railway. Two of these magnetic targets were further investigated with ground magnetic surveys and two aircore drillholes (total 213 metres), which bottomed in mafic quartz monzodiorite and hydrothermally altered granodiorite. No kimberlitic, lamproitic or carbonatitic mineralogical associations, or significant base or precious metal assay values, were returned from core sampling of these basement rocks. The apparent thickness of overlying Cainozoic sediments in this area precluded serious consideration of using calcrete or soil sampling programs to broaden the commodity search to include Ernest Henry - style Cu/Au and Challenger - type Au objectives.