TYPICAL FEATURES OF THE SEDIMENTATION PROCESS IN THE SEA OF JAPAN

Sedimentation processes in the Sea of Japan are characterized by certain, specific features, depending on the climatic zonality, the hydrologic environment, the geological shore-line structure and the bottom morphology of the basin. In consequence of gravel and pebbles being scattered over great distances by floating ice, accumulation of glacial marine deposits takes place in the northwest part of the sea and the Tartar Strait. Zones of sediments with high organic-carbon content are confined to fine-silt deposits of the continental piedmont slope. The organic-carbon content in the sediments decreases considerably towards the central part of the basin. Evidently, this depends on the fact that marine water contains great quantities of free oxygen and the organic matter is oxidized during the prolonged period of settlement anddeposition, on the sea bottom. The distribution of such organic sediment constituents as amorphous O₂ and calcium carbonate fully depends on the distribution of cold and warm currents. The zone of maximum SiO₂-content forms a band along the western sea shore skirted by the cold Primor'ye current. Calcium carbonate accumulation in the sediments takes place chiefly in arenaceous sediments of the Futhern part, within the warm Tsushima current zone. Zones of maximum iron and manganese contents in the sediments are found near the western coast which is composed cheifly of basic magmatic rocks.

A study of recent Sea of Japan sediments shows that the specific features of each individual basin exercise considerable influence upon the laws governing the sedimentation process.—Auth. English summ.