Rare-Earth Elements in Dictyonema Shales of the Baltic Sedimentary Paleobasin.

The results of a study of rare-earth metals in dictyonema shales of the Paleozoic Baltic sedimentary basin are presented. In the territory of the studied Kaibolovo–Gostilitsy prospecting area, high up to potentially industrial rare-earth element (REE) contents were confirmed based on a large factual and analytical material. The average REE concentration was 289 g/t with maximums up to 724 g/t. REEs were found in dictyonema shales in various forms (mineral, organic, ionic, molecular, and colloidal). The occurrence of REEs in the mineral matter of dictyonema shales predominated. The fraction of heavy (and most valuable) lanthanides (15.6% on a total basis) in the test dictyonema shales was higher by a factor of 2 than that in ore deposits. This fact and the presence of large geological REE resources in the dictyonema shales of the Baltic region of Russia determine the need for their integrated development with other associated components. [ABSTRACT FROM AUTHOR]