Uranium occurrences in albitized rocks

The mineralizations described in the Soviet literature are characterized by several phases leading to a distinct mineral zonation. The mineral association depends on the source rock. Important processes are the replacement of quartz and feldspar by albite, formation of Na-hornblendes at the expense of common hornblende and biotite, as well as the development of epidote and aegirine. Cataclastic processes accompany the albitization. In addition to uranium, the formation of zircon is characteristic. The association with phosphate (Itataja) as well as REE and Th (Espinharas) is characterstic for the Brazilian occurrences. The mineralization of uranium follows steeply dipping structures down to depths of more than 1500 m (USSR). The initial investigations of the Kitongo occurrence in northern Cameroon show the presence of four albitite types (arfvedsonite albitite, arfvedsonite-riebeckite albitite, cataclastic riebeckite albitite, and aegirine albitite) which can be assigned to two formation phases. Uranium ore occurs in cataclastic riebeckite albitite and aegirine albitite, as well as together with carbonate along later veinlets. The extent of the occurrence is not definitely determined, the investigations will be continued. (orig./HP)