Seafloor Surface Sediments of the North Atlantic on the Profile Along 59.5° N.

Analysis of the lithological, isotope-geochemical, and micropaleontological parameters of the surface layer of bottom sediments in the North Atlantic was carried out at 26 stations on the profile along 59.5° N. The distribution of moisture content and grain size of sediments reflects vertical/circumcontinental zoning, since fine-grained and water-saturated material accumulates in the deepest parts of the Iceland Basin and the Labrador and Irminger seas, which are farthest from land. Larger masses of calcium carbonate also form there, but organic carbon is unevenly distributed. Both vertical/circumcontinental and climatic (circulation of warm North Atlantic water) zoning affect the mineral composition of the >0.063 mm sediment fraction. Accumulation of diatoms, radiolarians, and planktic foraminifers in sediments reflects both vertical/circumcontinental and, to a greater extent, climatic zoning. Variations in the oxygen and carbon isotopic ratios in the tests of benthic and planktic foraminifers require comprehensive interpretation involving data on the parameters of various surface and bottom water masses. The distribution of planktic microfossil assemblages according to cluster analysis shows distribution areas of different water masses with a distinct boundary along the eastern margin of the Subpolar Gyre. The distribution of cluster assemblages of benthic foraminifers does not correspond much to that of planktic microfossils, reflecting division of the study region into abyssal and shallow areas. [ABSTRACT FROM AUTHOR]