(Table 1) Composition of bottom sediments from the East Pacific

Adsorption of ion, nickel, cobalt, and manganese from ocean water by calcareous sediments, diatomaceous ooze, hydrogenous sediments, and red clay was studied under close to natural conditions using a tracer method. It was found that hydrogenous sediments selectively remove manganese from seawater. This may be associated with formation of chemical compounds between manganese and sediment material. It was also found that nickel, manganese, and iron exist in the ocean in several ionic and neutral forms. Cobalt typically present in only one ionic form Co(2+).

Concentrations of chemical elements in bottom sediments from the Southeast Pacific

Data from the Appendix to the PhD Thesis of the author.

(Table 1) Relarive abundance of foraminiferal species in the surface layer of bottom sediments from the Atlantic Ocean

Quantitative ratios of tests of planktonic foraminiferal species in thanatocoenoses within the surface layer of bottom sediments from Iceland to the Equator are described. Subarctic, boreal, subtropical and tropical types of thanatocoenoses and their subtypes are distinguished. Each subtype corresponds to a 2-3°C interval of mean annual temperature of the upper layer of ocean water. Comparison of fossil thanatocoenoses from Quaternary sediment cores with recent thanatocoenoses offers new potentials for paleotemperature analysis.

(Table 1) Mineral composition of sand- and silt-sized fractions of bottom sediments from the Romanche Trench

A study was made of mineral composition of sand- and silt-sized fractions of recent clastic (riftogenic) sediments and solidified deposits collected from the bottom of the Romanche Trench during the first voyage of R/V Akademik Kurchatov. Similarity between mineral compositions of sediments and bedrocks (ultrabasites, gabbroids, diabases) was established. This similarity is a basis for considering the mineral complex of the deposits that have been derived from the bedrocks of the trench slopes, and have formed due to their submarine denudation accompanied by tectonic crushing. The same mineral composition was found in pieces of older consolidated deposits; this suggests that conditions of sedimentation similar to those at recent times have existed for a long time in the Romanche Trench.

(Table 1) Mineral phosphorus contents in bottom sediments and interstitial waters of the Southeast Atlantic

Concentrations of mineral phosphorus in interstitial waters from sediments of the Southeast Atlantic generally increases from the ocean bed to the continental slope and shelf. In diatomaceous oozes of the Southwest Africa shelf, phosphorus concentration in fresh interstitial waters reaches 2.5 mg/l in absence of phosphorite concretions and 0.1-0.7 mg/l in their presence. After prolonged storage of samples concentration of dissolved mineral phosphorus sometimes increases up to 7-8 mg/l. The key factor regulating phosphorus content of solid and liquid phases of unaltered sediments are content and composition of organic matter.

(Table 1) Grain size composition and heavy metal speciations in bottom sediments of the Ussuri Bay, Sea of Japan

Changes in concentration levels and speciation of heavy metals during sedimentation on example of a typical semi-closed bay, where bottom sediments have formed due to river run-off, are under consideration. It is shown that due to desorption of mobile manganese, zinc and copper entered the bay with river suspended matter, their total contents in bottom sediments decrease and percentages of lithogenic forms increase. Contents and speciation of iron in bottom sediments are determined by its participation in coagulation of river colloids in the mixing zone and by mechanical differentiation of sedimentary material.

Uranium in Black Sea bottom sediments

Results of uranium content determinations in 76 samples of surface layer bottom sediments, from sediment cores, and deep-sea drilling cores are reported. These data confirm previously established regularities of uranium distribution in Black Sea bottom sediments. The main factors of its concentration are hydrochemical features of the hydrogen sulfide enrichment zone and enrichment of deep-sea sediments in organic matter resulting to increase (4-6 times) of uranium content in comparison with its average content in sedimentary rocks.

(Table 1) Iron and manganese speciations in surface layer bottom sediments of the Pacific Ocean

Distribution of iron and manganese speciations in ocean sediments of a section from the coast of Japan to the open Pacific Ocean is under consideration. Determinations of total iron, as well as of reactive iron contents and of total manganese, as well as of Mn4+ contents have been done. Significant increase of total Fe content in sediments from the coast to the pelagic zone occurs without noticeable increase in reactive Fe content. Presence of layers of volcanic and terrigenous coarse clastic material in clayey sediments results to sharp change in iron content. Manganese content increases from near coastal to pelagic sediments more than 10 times; oxidation degree of sediments also increases. There are three types of bottom sediments different by contents of iron and manganese forms: reduced, oxidized (red clay), and transitional. Content of total Fe is almost does not change with depth in sediments, content of reactive Fe increases in reduced sediments, and decreases in oxidized ones. Manganese content in red clay mass increases several times.

(Table 1) Chemical composition of phillipsites from pelagic bottom sediments of the Transpacific profile

Results of petrographic, chemical and X-ray studies of zeolites in sediments in the Transpacific lithological profile from the coast of Japan to the coast of Mexico are reported. For ocean phillipsites constancy of Si/Al ratio (2.44-2.87) and unstable cation composition in quantitative predominance of potassium over sodium are characteristic. Two groups of ocean phillipsites are distinguished: of deep-water basins and of submarine rises. The first spread over broad areas of the pelagic zone, and are formed by diagenetic transformation of fine dispersed pyroclastic material in minimum sedimentation rates, the latter occur locally - in areas of basaltic volcanism manifestations.