LAUSR

The first study of the full chemical composition of Triassic phosphorites from Kotelny Island and Jurassic–Cretaceous phosphorite from the Egorjevsk deposit showed that the former are relatively enriched in some trace elements, but their general distribution patterns are identical and differ from those of sedimentary rocks. The trace element pattern of phosphorites is similar to that of carbonaceous shales, which is related to their genetic similarity regardless of the age. The presence of Triassic phosphorites in the Arctic region indicates that phosphates were accumulated on the East European Platform in three stages, the Triassic, Jurassic, and Cretaceous, which led to the formation of series of economic-grade deposits.