The plant biostratigraphy of the Cenozoic coal-bearing formations in Primorye, Russian Far East

The paper presents a review of stratigraphy, lithology and metallogeny of the Paleogene and Neogene coal basins from the Primorye region of southeast Russia. The stratigraphic division of the studied sections is based on the abundant fossil plant material, represented by leaf impressions and, in lesser amounts, fruit and seed fossils, as well as detailed palynological analyses. Previously published U-Pb zircon and K-Ar bulk-rock dates of volcanic and volcaniclastic rocks were also used. As a result of this study, five stages of Cenozoic sedimentation are distinguished, namely the Late Paleocene, Early Eocene, Late Eocene, Late Oligocene, and Early Miocene. The Early Eocene, Late Eocene, Late Oligocene coal-bearing units carry high concentrations of critical elements and include 3 of the 7 most germanium-enriched coal deposits in the world. In addition, coals in the Pushkino, Pavlovka, Vanchin, Rakovka, and Rettikhovka basins contain numerous occurrences of rare earth elements and yttrium; gold occurs in the Pavlovka, Vanchin, Rakovka, Krylovka, Sredne-Bikin, and Verkhne-Bikin basins; uranium occurs in the Pavlovka, Rakovka, Rettikhovka, and Glukhovka basins; while zirconium and niobium occur in the Pushkino basin.