Representative uranium deposits and occurrences exclusive of sandstone impregnations and quartz conglomerates

Abstract

All the known non-sandstone and non-quartz-conglomerate types of uranium deposits and occurrences were reviewed to focus on geologic environments from which unknown large economic types might be expected. One or more representative examples of each type was selected and its major occurrence characteristics identified, following a new limited genetic classification. Potential significance was judged by capacity of the mineralization process to produce large deposits, rather than by the size and grade of known examples. The precedent for this approach is set by uranium exploration history: Exploration occurred in spurts stimulated by demand beyond the capability of known deposits and distinguished by recognition of new types of larger, richer deposits which could supply the demand. Stagnation in the 1960's and 1970's of the discovery rate for “conventional” sandstone impregnations and quartz-pebble conglomerates which contributed the bulk of uranium production, illustrated the need for another innovative spurt. The study encompassed the then “unconventional” types of uranium deposits. However, during the investigation, exploration discovered so many large rich “unconventional” deposits that the connotation “conventional” (on the production basis) embraced them. This included the Rossing late-magmatic replacement dissemination and a number of impregnation-replacement masses related to Proterozoic unconformities in Canada and Australia. These types were included in the original project and are retained in this discussion, but their inclusion reduces the significance, precision and impact originally intended by designating the entire range of considered deposit types as “unconventional”. Accordingly the designation conventional/unconventional has been removed or subdued. However, the principle that surprising discoveries introduce new economic types of deposits which were subtly evidenced in known occurrences and shift the designation of conventional, was emphatically confirmed by both this project and concurrent exploration. Recognition of this principle lends potential significance to the remaining unconventional deposits and occurrences discussed. Their occurrence parameters may contain clues to yet other unknown types of large rich deposits. However, little effort was made in this paper to identify specific potentially economic exploration targets.