Assessment of Rare Earth Elements Fractionation in Sandstone and Magmatic Uranium Ores: Implications for Deposit Typing

This paper presents a comparative determination of rare earth elements (REEs) in sandstone-type uranium ore samples from Kazakhstan using a proposed rapid ICP-MS method following microwave digestion in a MARS 6 system with a mixed acid solution of HNO3, HCl, and HF. To validate the rapid REE determination method, comparative measurements were performed using a certified uranium ore reference material provided by Ore Research & Exploration, representing sandstone-hosted uranium mineralization from a Tanzanian deposit (OREAS 120). Fractionation patterns of chondrite-normalized REEs in uranium ores from Kazakhstan were evaluated. Comparative data on REE distribution in sandstone- and magmatic-type uranium deposits from Australia and Tanzania are presented. Uranium ores of magmatic- and sandstone-hosted types exhibit distinct REE distribution patterns, reflecting differences in the nature of ore-forming processes. This study provides chondrite-normalized REE distribution profiles for major uranium deposit types from three countries, which are subsequently used to assess uranium ore paragenesis through simple linear regression analysis. This study is intended as an applied comparative synthesis of REE fractionation patterns in genetically contrasting uranium deposits, with particular relevance to deposit classification.