Phosphorite potential of cretaceous and Paleogene rocks in the Kaliningrad and southeastern Baltic regions

Geologic and paleogeographic settings of the Upper Jurassic, Cretaceous, and Paleogene phosphorite-bearing rocks in the Kaliningrad and southeastern Baltic regions are considered. The paper discusses structures of the phosphorite-bearing sections, outlines phosphorite types, and compares them with the adjacent regions and phosphorite-bearing basins of the East European Platform. It is noted that the age of Meso-Cenozoic phosphorite-bearing horizons in the Kaliningrad and southeastern Baltic regions are similar or akin to the age of phosphorite-bearing horizons in other regions of the East European Platform. The age also matches that of ancient weathering crusts in provenances. Data on the composition of rare and rare earth elements in phosphorites from the northwestern basins of the East European Platform are used to estimate the role of igneous rocks, in particular, alkaline mafic-ultramafic rocks of Karelia that delivered phosphorus to sedimentation basins.