Karoo airborne geophysical survey: Report on aerial radiometric anmalies of block 2

Forty-three uranium anomalies were selected from the analogue spectrometer records of Block 2 of the karoo airborne geophysical survey. The aerial geophysical data and the results of the ground follow-up are described seperately in this report. The anomalies were plotted onto 1: 50 000 scale topocadastral maps and the anomaly co-ordinates scaled off and tabulated. They are als shown on the 1: 250 000 scale maps, which are included in Volume I of this report. Results of the ground follow-up of forty-three radiometric anomalies of the Karoo airborne geophysical survey in Block 2 are described. Significant uranium mineralisation occurs only in fluvial channel sandstone of the Beaufort Group and twenty-three anomalies have been followed-up. The maximum spectrometer-derived concentrations at these anomalous areas are between 42 ppm and 8 666 ppm eU3O8 and the occurrences are located in both the Abrahamskraal and Teekloof Formations of the Beaufort Group. The uranium potential at fifteen of the twenty-three anomalies is good, since the morphology of the sandstone bodies is either multi-storey tabular or composite and subsurface mineralised sandstone is possible. The ribbon morphology of the sandstone bodies, the low surface uranium concentrations (less than 128 ppm eU3O8), the presence of dolerite near the anomaly or the removal by erosion of the sandstone body away from the surface uranium occurrences reduces the uranium potential at the other eight anomalies over the Beaufort Group. Of the remaining twenty anomalies one is located over the Ecca Group, another over chert of the Beaufort Group, five are spurious and 13 unexplained