Ancient Marine Phosphorites

Marine phosphorites have been studied for more than a hundred years, both because of their commercial value as fertilizer and because of their importance to sedimentary petrology. Phosphorus is, of course, one of the basic plant nutrients and is intimately involved in biospheric processes; however, its role in biogenic and chemogenic sedimentation is difficult to study and is not completely understood. Marine phosphorites on the seafloor today occur on continental shelves, rises, and seamounts. This article reviews phosphorite research.