Features of Formation of the Sedimentation and Mass Accumulation Rate in Western Black Sea Bottom Sediments

The article is devoted to studing of the features of sedimentation on the bottom of the northwestern shelf and western deep-water area of the Black Sea based on an analysis of our own and published data obtained by bottom sediment radioisotope geochronology. It was determined that the relationship between the mass accumulation rate and primary production was linear, due to the aggregate biogeographic, hydrological, and hydrochemical conditions. The features of bottom sediment formation in the open part of the sea were associated with the presence of hydrogen sulfide (H 2 S) in deep waters (deeper than 100–200 m). It was shown that 20 (on the continental slope) and 17 g/(m 2 year) of particulate organic matter (in the deep-sea basin) entered from the oxygen-containing zone. In this case, the predominant fractions in bottom sediments were mineralized biogenic matter: 54 and 68.5%, respectively, in these areas. The contribution of organic, mineralized biogenic, and lithogenic sedimentary matter to the formation of the mass accumulation rate was estimated, and changes in their ratio with distance from the coast and estuaries were shown. Based on the nature of the formation of the mass accumulation rate, three groups of sea areas were identified in which the ratio of biogenic and lithogenic components in absolute masses reflected a change in their role of these components in bottom sediment formation.