Entrainment of fine-grained surface deposits into new ice in the southwestern Kara Sea, Siberian Arctic

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

“…77%; Dethleff 2005; this study). Dethleff & Kuhlmann (2009) also found enhanced medium and fine silt content in the SIS of the south-western Kara Sea, with individual concentrations of more than 84%, which is even higher than the average medium and fine silt content in Kara Sea shelf surface deposits (ca. 75%) determined in the present study.…”

“…Arctic SIS are typically much finer grained (i.e., contain more silt and clay) than the circum-Arctic shelf source sediments, with a clear emphasis on the 2-63-mm silt fraction (e.g., Reimnitz et al 1998;Dethleff 2005;Dethleff & Kuhlmann 2009). Clark & Hanson (1983) identified four textural types (type I-IV) of icetransported fine-grained bottom sediment in the Arctic Ocean (compare Figs 2 and 3b), which rely widely on the silt distribution.…”

“…Our knowledge of the hydrodynamic mechanisms of turbulent SIS entrainment in the Kara Sea is primarily based on modelling efforts (Harms et al 2000;Sherwood 2000;Smedsrud 2003). In a sedimentological study, Dethleff & Kuhlmann (2009) investigated the entrainment of silt and clay into new ice formed in a shallow, coastal flaw lead (long extended open water between fast ice and drift ice) in the south-western Kara Sea. The study showed that newly incorporated SIS had the same composition as the shelf surface under the flaw lead.…”

“…Sea-ice sediment entrainment occurs during late autumn and winter in shallow, ice-free shelf areas (autumn open water and polynyas). In the process of suspension freezing, turbulent mixing of the water column leads to the incorporation of shelf sediments into new ice (Campbell & Collin 1958;Reimnitz et al 1992;Dethleff & Kuhlmann 2009). Suspension freezing is driven by turbulent mixing that brings frazil and suspended sediment into contact in the water column, where they form buoyant, sediment-laden flocs that are incorporated into the newly forming ice cover.…”

Unraveling Sediment Transport Along Glaciated Margins (the Northwestern Nordic Seas) Using Quantitative X-Ray Diffraction of Bulk (< 2mm) Sediment

“…1) (Eggertsson, 1993;Dyke et al, 1997;Tremblay et al, 1997). Sediments in the sea ice "…contain on average more than 94% silt and clay" (Dethleff and Kuhlmann, 2010), and the process of sediment entrainment in sea ice (Reimnitz et al, 1987;Darby, 2003;Dethleff and Kuhlmann, 2009) results in an enhancement of the fine-fractions relative to sediments on the sea floor. Dethleff and Kuhlmann (2010) were able to distinguish between eastern (Kara Sea) and and western (Laptev Sea) sources based on clay mineralogy.…”