Clay‐mineral distribution in surface sediments of the Eurasian Arctic Ocean and continental margin as indicator for source areas and transport pathways — a synthesis

Abstract

G. 1999 (March): Clay-mineral distribution in surface sediments of the Eurasian kctic Ocean and continental margin as indicator for source areas and transport pathwaysa synthesis. Boreas, Vol. 28, pp. 215-233. Oslo. ISSN 0300-9483. Clay-mineral distributions in the Arctic Ocean and the adjacent Eurasian shelf areas are discussed to identify source areas and transport pathways of terrigenous material in the Arctic Ocean. The main clay minerals in Eurasian Arctic Ocean sediments are illite and chlorite. Smectite and kaolinite occur in minor amounts in these sediments, but show strong variations in the shelf areas. These two minerals are therefore reliable in reconstructions of source areas of sediments from the Eurasian Arctic. The Kara Sea and the western part of the Laptev Sea are enriched in smectite, with highest values of up to 70% in the deltas of the Ob and Yenisey rivers. Illite is the dominant clay mineral in all the investigated sediments except for parts of the Kara Sea.The highest concentrations with more than 70% illite occur in the East Siberian Sea and around Svalbard. Chlorite represents the clay mineral with lowest concentration changes in the Eastern Arctic, ranging between 10 and 25%. The main source areas for kaolinite in the Eurasian Arctic are Mesozoic sedimentary rocks on Franz-Josef Land islands. Based on clay-mineral data, transport of the clay fraction via sea ice is of minor importance for the modern sedimentary budget in the Arctic basins.

Fram Strait sea-ice sediment provinces based on silt and clay compositions identify Siberian Kara and Laptev seas as main source regions

“…Western Laptev Sea and the Kara Sea bottom sediments show high contents of smectite, whereas eastern Laptev, East Siberian and Chukchi seas bottom deposits, as well as North American and Canadian shelf source sediments, are dominated by illite throughout (Wahsner et al 1999). Reimnitz et al (1998) reported an average Table 3, stations 13-23, a-f; illite, 50 versus 21%, 9.3 versus 4.0 SD, Table 3, stations 4-6, 9-12 and 24-35), whereas kaolinite and chlorite contents are similar (kaolinite, 5 versus 5%, 2.0 versus 1.6 SD; chlorite, 25 versus 18%, 1.7 versus 3.5 SD).…”

Smectite composition as a tracer of deep circulation: the case of the Northern North Atlantic

“…Smectites have been locally reported in Siberian Arctic surface sediments, in particular in the Laptev Sea shelf area (20-40% of smectites, Nùrnberg et al, 1994). A recent synthesis demonstrates the variability of smectite content in surface sediments from the Eurasian shelf seas and the adjacent Central Arctic Ocean (Wahsner et al, 1999). Smectite contents are low (<5-20%) in Eurasian Arctic Ocean but increase in shelf areas, in the inner Laptev and Kara seas (mean smectite content of 26 and 60%, respectively).…”

“…These areas represent the main source of smectites out of the Arctic Ocean. Smectites were supposed to be derived from the erosion and weathering of Mesozoic basalt complexes in the Siberian Hinterland, then transported by rivers to the Kara and Laptev seas (see references in Wahsner et al, 1999). Smectite particles may have been transported by cold currents to the North Atlantic, a smectite maximum being evidenced along the pathway of the Transpolar Drift (Nùrnberg et al, 1994) which drives sea ice from the Siberian shelf to the Fram Strait.…”

Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

“…Spatial variation in mineral composition of surficial sediments along the western Arctic margin has been investigated in a number of studies using different methodological approaches but showing an overall consistent picture (e.g., Naidu et al, 1982;Naidu and Mowatt, 1983;Wahsner et al, 1999;Kalinenko, 2001;Viscosi-Shirley et al, 2003;Darby et al, 2011;Kobayashi et al, 2016). A recent study of mineral distribution in sediments from the Chukchi Sea and adjacent areas of the Arctic Ocean and the Bering Sea suggests that the quartz / feldspar (Q / F) ratio is higher on the North American than on the Siberian side of the western Arctic ( Fig.…”