FEATURES OF LATE HOLOCENE SEDIMENTATION IN THE CHUKCHI SEA INFERRED FROM GRAIN SIZE AND MINERALOGICAL ANALYSES OF BOTTOM SEDIMENTS
E.G. Vologina1, A.N. Kolesnik2, O.N. Kolesnik2, S.A. Selyutin2
a:2:{s:4:"TEXT";s:260:"1Institute of the Earth’s Сrust, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia
2V.I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences,
Vladivostok, Russia
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Keywords: Chukchi Sea, bottom sediments, rates of recent sedimentation, grain size composition, light and heavy fraction minerals, ice rafting
Abstract
The aim of the work is to identify the features of modern sedimentation in the Chukchi Sea based on the study of the material composition of Late Holocene bottom sediments. Analytical methods included grain size and mineralogical analyses. The results of dating by 210Pb and 137Cs were used. The deposits are represented by clayey silt and silty clay, containing sand admixture and isolated gravel grains and pebbles. The content of coarse-grained material increases slightly in the upper parts of the studied sections. This is probably due to an increase in the contribution of ice transport to the modern sedimentation of the Chukchi Sea as a result of climate warming. The composition of thin and fine-grained sandy material (fraction 0.25–0.05 mm) is dominated by light fraction minerals. Volcanic glass was discovered in sediments sampled in the southern and central parts of the Chukchi Sea, the source of which may be the volcanoes of Alaska, Aleutian Islands and the Kamchatka Peninsula. The transport of volcanic glass grains is apparently carried out by Pacific currents directed from south to north through the Bering Strait. Sediments collected in the southern, central and northern parts of the Chukchi Sea differ in grain size and mineralogical composition. This is probably due to the distance from the coast line and from the provenance areas, and is also caused by different rates of sedimentation.
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