Phosphorus in Oceanic Sedimentogenesis

Balance calculations, characterizing the behavior of phosphorus at essential stages of sedimentogenesis, were made using published and original data. River runoff supplies annually to the ocean 1.4-3.1 million tons of dissolved phosphorus and 12.2-14.3 million tons of suspended phosphorus, which precipitates mainly on the continental margins. Dissolved phosphorus in an amount of up to 2.9 million ton/year is deposited from sea water predominantly as a result of bioassimilation and biosedimentation, and a much smaller quantity of this element coprecipitates with iron hydroxides. The average phosphorus content in surficial oceanic sediments is similar to that in the sedimentary rocks of the earth's crust, except for red clays, volcanogenic and metalliferous sediments appreciably enriched in phosphorus. The estimated rate of phosphorus accumulation in Late Quaternary oceanic sediments (about 16 million ton/year) is equal to the rate of phosphorus supply from continents and is by almost an order of magnitude higher than the average rate of phosphorus accumulation in the Phanerozoic sedimentary rocks. This phenomenon may be explained by a number of factors, including the increased rate of recent continental denudation, inadequacy of present -day observations, and incompleteness of the geological record