MOVING UP THE LEARNING CURVE FOR DISCOVERY OF URANIUM DEPOSITS AND URANIUM GEOCHEMISTRY

To explore effectively for uranium or any other metal deposits, we must move up the learning curve of discovery, ultimately moving into research and technology driven exploration. As a recent example, elements mobilized from a deeply buried unconformity-type uranium deposit in the Athabasca Basin, the processes that mobilize these elements and how they are manifest in a variety of media at the surface were examined. To trace the geochemical signal from the deposit over 400m to the surface, drill core near the deposit, clay-size fractions separated from the A, B and C soil horizons and tree cores, twigs and needles over and far from the deposit were collected. Evidence for element migration from the deposit is indicated by radiogenic Pb and microbial C and N isotopic compositions in both fractures and background core, as well as correlations among U, Ni, V, Co, and As in fractures and surface media, as expected from the deposits. Correlations among Mg, P, Ca, Sr, REEs and K concentrations are indicative of elements from the alteration halo around the deposit. The processes by which elements and isotopes get from the deposit to the surface appear to be associated with microbial activity, with one sample having microbes actually preserved on a fracture surface. Multi-element analysis including Pb isotopes of the clay-sized fractions of all three soil horizons provides compelling evidence that a robust geochemical signature exists that appears to reflect U mineralization present beneath more than 400m of Athabasca Sandstone. These effects are applicable to all types of uranium deposits to varying degrees and should be integrated into learning curves for effective exploration of uranium and other types of deposits.