Exploration for possible Tertiary or Mesozoic roll-front type, fluvial sediment - hosted secondary uranium deposits, which could be related to a large aerial radiometric uranium channel anomaly recorded from an area bordering the south-western side of Lake Eyre North, did not proceed beyond the compilation of existing geological and geophysical data and an initial field reconnaissance, owing to the apparent lack of suitable redox cell host rocks (porous sandstones) in the locality. Only a thick sequence of palaeo playa lake sediments was observed, outcropping sporadically along several ground traverses made between the Oodnadatta Road and the lake shore. It is up to 100 m thick and consists of bedded gypsiferous mudstones interlayered with ferricretes and massive pure gypsum beds. Both the ferricretes and mudstones have gamma radiation levels approaching 2 to 3 times the regional background. It is surmised that the contrast in surface radioactivity passing from these outcropping beds into the lower background, younger alluvial and colluvial sedimentary cover would plausibly account for the aerial radiometric response.