Report on exploration, EL 845 Ewaninga Prospect, June to December, 1973.

Abstract

Uranium mineralisatiUranium mineralisation is hosted by sandstone of the Undandita Member of the Brewer Conglomerate, a Devonian-carboniferous sequence in central Australia. Airborne and car borne radiometric surveys revealed two strong anomalies which were covered by a line of grid, foot borne radiometric and geochemical surveys. Trenching and detailed mapping was carried out on anomalies. This defined strong secondary uranium mineralisation which was found to be associated with transgressive colour changes in the sandstone. This was further investigated by drilling on both anomalies. In both cases, extensions of the mineralisation were found at depth, associated with the transgressive interface between two major colour types in sandstone. The mineralisation appears to have been deposited by oxidising ground waters in the sandstone, but the reasons for the locations of mineral concentrations are at present not clear. The mineralisation is rather irregular, both on a broad and a small scale. on is irregular and appears to have been deposited from oxidising ground water.