Glaciomarine Sediment Flux and Transportation Mechanisms,

Kronebreen/Kongsvegan, Kongsfjorden, Svalbard

By Theo Barnhart

Whitman College, Walla Walla WA

 

Arctic tidewater glaciers are likely to respond rapidly to changes in climate, due to a variety of climate forcing mechanisms. This study is designed to assess how these glaciers are now responding to these changes. We collected marine sediment samples near Kronebreen/Kongsvegan, a polythermal subpolar tidewater glacier in Kongsfjorden, Svalbard, over the summer melt season of 2009. CTD/OBS and meteorological data were also collected to characterize this dynamic Arctic system. One-to-three-day modern sediment records were collected near the top, the middle, and the bottom of the fjord water column with mooring locations ranging in depth from 20 to 120 m below sea level. Accumulation rates from the bottommost sediment traps of 380, 220, and 160 kg/m2/yr were found at 0.45, 0.75, and 1.00 km, respectively, from the ice-marginal delta on the southern edge of Kronebreen/Kongsvegan. Sedimentation rates appear to decrease logarithmically away from the ice-marginal delta. Couplets of coarse and fine sediment were found in sediment traps from the meltwater sediment plume indicating a diurnal meltwater discharge pattern. The couplets may be due more to solar incidence than to temperature and precipitation. Tidal current velocity may play a role in differentiating coarse and fine particles as they are released from the meltwater sediment plume, but there is not sufficient evidence to test for this fully.