The Svalbard REU has been studying modern processes in the Linne’ Valley since 2003. Our ultimate research objective is to calibrate the lamination stratigraphy of cores recovered from Linne’vatnet by 1) comparing core stratigraphies with the instrumental weather record of the past 100 years) and 2) by interpreting annual sediment trap stratigraphies in light of measured conditions on the land and glacier, and in the meltwater stream and lake.

Sediment trap data over the past 4 years indicates that annual sedimentation cycles do occur in the basin (coarsest sediment is deposited during the spring and finer textures are deposited during the ablation season) and that high discharge stream events add complexity to the varve stratigraphy. Spring sediment traps deployed just prior to the onset of the melt season indicate that as much as 90% of the collected sediment is deposited during the spring melt event prior to the initiation of glacier ablation. Differences between traps positioned at different water depths has been qualitatively related to sediment distribution processes in the basin. Monitoring of suspended sediment concentrations proximal and distal to the glacier indicates that more than 80% of the suspended sediment released by the glacier is deposited in the meltwater system during the summer ablation season.

To further refine the timing and cause of textural variations observed in the sediment traps additional monitoring was initiated during the ‘06/’07 sedimentation year. We installed two automated cameras (to monitor snowline elevation, landscape snow cover, inflow stream stage, lake ice conditions and sediment plume occurrence) and we established a snow-depth monitoring site, deployed a water turbidity logger and an intervolometer sediment trap to record the timing and rate of sedimentation in the lake. This new monitoring compliments ongoing monitoring of weather conditions, glacier ablation, inflow and lake water temperature at different locations and at various depths in the lake.

The 2007 melt season was characterized by two prominent turbidity events in the lake in late June and early July. The first turbidity event was associated with warm air temperatures, high levels of radiation and a rapid loss of snow cover. The largest turbidity event (90 NTU), however, was associated with a subsequent rain event (15 hour lag) during which time inflow stream stage peaked and lake ice rapidly degraded. Lake temperature data indicated that during both of these sedimentation events, sediment was distributed in the lake by interflow conditions. These observations suggest that for glacier-fed lake systems with intervening fluvial systems, high stream discharge (in response to rapid snow melt or heavy rainfall) is responsible for annual silt deposition and that finer textures are associated with suspended sediment flux during the ablation season. Studies attempting to reconstruct paleo glacier mass balance should focus on glacier-fed lake systems with small drainage areas having short fluvial systems.