The use of lanthanides for the reconstruction of Phanerozoic and Proterozoic sedimentation environments exemplified by sections in the cover and basement of the East European platform

Criteria were established for the estimation of the lanthanide composition of sedimentary complexes for the reconstruction of sedimentation conditions. The distribution of lanthanides was investigated in phosphorites and sedimentary rocks from the cover of the East European platform, and published data on the geochemistry of phosphorites from Eurasia were analyzed. Indicator lanthanide ratios were established for the determination of the climate and depth of sedimentation, and the possibility of the use of rare earth elements for the facies settings and transgression-regression cycles of sedimentation was demonstrated. The sedimentation conditions of the iron formations of the Proterozoic Kursk and Krivoi Rog sedimentary groups were inferred from the distribution of lanthanides: the hematite and magnetite quartzites are the deepest water complexes of the sedimentation profile; the climatic conditions of sedimentation were estimated as humid for shale subformations and humid-semihumid for iron formations; the depths of sedimentation in the Kursk basin was 50−300 m; the sources of iron were the material of weathering profiles and endogenous influx.