RECENT DEPOSITION ENVIRONMENTS IN THE CHUKCHI SEA AND ADJACENT AREAS OF THE ARCTIC OCEAN: EVIDENCE FROM Q-CLUSTER ANALYSIS OF SEDIMENT COMPOSITIONS AND GRAIN SIZES
A.N. Kolesnik, A.S. Astakhov, O.N. Kolesnik
V.I. Il'ichev Pacific Oceanological Institute, Far East Branch of the Russian Academy of Sciences, ul. Baltiiskaya 43, Vladivostok, 690041, Russia
Keywords: Surface bottom sediments, chemical and grain size compositions, authigenic ferromanganese and carbonate phases, cluster analysis, clastic and biogenic deposition, redox conditions and diagenesis, Chukchi Sea, East Siberian Sea, Beaufort Sea, Arctic Basin
Abstract
Deposition environments in the Chukchi Sea and adjacent areas of the Arctic Ocean are studied by the Q -cluster analysis of compositions, particle sizes, and other properties of surface bottom sediments. Analysis of more than 4700 numeric values allowed mapping fifteen clusters distributed over the seafloor according to deposition environments. Chemical and statistical data confirm the predominance of clastic sedimentation and mainly mechanic sorting of sedimentary material. At the same time, the major-element composition trends correspond to Si decrease and Al increase seaward. Biogenic deposition is of inferior scale and shows up as relative enrichment in total organic carbon, Ca, Mg, Ba, Sr, and some other biogenic and chemogenic components in sediments. Clastic and biogenic deposition, with accumulation of Fe, Mn, V, Ni, Cr, Co, and other elements, as well as precipitation of authigenic growths, occurs within areas of seafloor having particular water chemistry, such as the Herald Canyon, the outer shelf, and the deepwater Arctic Ocean.
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