Weathering and phosphorite genesis

The idea of the relation between phosphorite genesis and weathering is base d on the corresponding concepts of N. S. Shatskii. Y. P. Kazarinov accepted this idea and substantiated that the epochs of intense phosphorite formati on coincided in time with the epochs of deep chemical weathering, G. I. Bus hinskii had a similar, though not guile identical, opinion that phosphorus involved in the formation of phosphorite-bearing deposits and basins is sup plied by rivers of the nearby plains in the regions of humid climate. Today many researchers hold to the idea of the significant importance of weather ing in phosphorite genesis. This idea has received further support for many global epochs of phosphorite formation (Early Ordovician, Late Jurassic, E arly Cretaceous, Late Cretaceous, Paleocene, Eocene, Miocene, etc.) and is treated as reasonably justified. At the same time, some epochs of deep chem ical weathering (e.g., Late Devonian) are characterized by high contents of dispersed phosphorus in rocks, which, however, did not participate in the formation of commercial phosphorite deposits.