Modern dirty sea ice characteristics and sources: The role of anchor ice

Abstract

Extensive dirty ice patches with up to 7 kg m−2 sediment concentrations in layers of up to 10 cm thickness were encountered in 2005 and 2007 in numerous areas across the central Arctic. The Fe grain fingerprint determination of sources for these sampled dirty ice floes indicated both Russian and Canadian sources, with the latter dominating. The presence of benthic shells and sea weeds along with thick layers (2–10 cm) of sediment covering 5–10 m2 indicates an anchor ice entrainment origin as opposed to suspension freezing for some of these floes. The anchor ice origin might explain the dominance of Canadian sources where only narrow flaw leads occur that would not favor suspension freezing as an entrainment process. Expandable clays, commonly used as an indicator of a Kara Sea origin for dirty sea ice, are present in moderately high percentages (>20%) in many circum‐Arctic source areas, including the Arctic coasts of North America. Some differences between the Russian and the North American coastal areas are found in clay mineral abundance, primarily the much higher abundance of chlorite in North America and the northern Barents Sea as opposed to the rest of the Russian Arctic. However, sea ice clay mineralogy matched many source areas, making it difficult to use as a provenance tool by itself. The bulk mineralogy (clay and non‐clay) does not match specific sources possibly due to reworking of the sediment in dirty floes through summer melting or the failure to characterize all possible source areas.

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

“…2e). These results are consistent with earlier studies showing that illite is a common clay mineral in Arctic sediments (Kalinenko, 2001;Darby et al, 2011), whereas chlorite is more abundant in the Bering Sea and the Chukchi shelf areas influenced by the BSI (Naidu and Mowatt, 1983;Kalinenko, 2001;Nwaodua et al, 2014;Kobayashi et al, 2016).…”

“…2d). This supports a notion that quartzrich but feldspar-poor sediments are derived from the North American margin by the BG circulation, whereas feldsparrich sediments are delivered to the Chukchi Sea from the Siberian margin by currents along the East Siberian slope (Vogt, 1997;Stein, 2008;Darby et al, 2011;Kobayashi et al, 2016).…”

“…These results are consistent with earlier studies including mineral determinations of shelf sediments and adjacent coasts (Vogt, 1997;Stein, 2008). Darby et al (2011) show a trend of a decreasing Q / F ratio in dirty sea ice from the North American margin to the Chukchi Sea and further to the East Siberian Sea. This zonal gradient of the Q / F ratio suggests that quartz-rich but feldspar-poor sediments are derived from the North American margin by the BG circulation, whereas feldspar-rich sediments are delivered to the Chukchi Sea from the Siberian margin by currents along the East Siberian slope (Kobayashi et al, 2016).…”

“…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.…”

Multidecadal to millennial marine climate oscillations across the Denmark Strait (~ 66° N) over the last 2000 cal yr BP

“…However, our estimates also include a calculation of the standard deviations of the estimate based on iterations of the 2 × 5 matrix (Andrews and Eberl, 2012); thus, we could account for nearly 100 % of the sediment composition by specific sample selection from the two source areas. Additional sediment sources would certainly be derived from icebergs that originated in Scoresby Sund and northeast Greenland and sediment entrained in sea ice from the Arctic Ocean (Andrews, 2011;Bigg, 1999;Darby and Bischof, 2004;Darby et al, 2011;Seale et al, 2011). Over the 100 yr interval ending ca.…”