| Summary: | Abstract: High Arctic sedimentary processes in a distal, proglacial lake (Linnévatnet, Spitsbergen, Svalbard) were studied in July and August of 2006 to understand links between climatic controls and suspended sediment entering the lake. Linnévatnet, one of the largest lakes in Svalbard (4.7 km long, 35 m deep), contains sediments dating from the late Pleistocene. Previous studies have attempted to quantify annual sedimentation rates and calibrate the lake’s lamination, however much remains unknown about the suspended sediment entering the lake from the south, and the seasonal mechanisms and processes of sediment deposition into the basin. This study provides a better understanding of summer sedimentation patterns in Linnévatnet, which in turn enables enhanced interpretations of the long-term Svalbard climate record preserved in the Linnévatnet sediment cores. Depth, temperature and transmissivity (turbidity) were recorded in water column profiles by a Seacat SBE 19 profiler over a three-week period. A local automated meteorological station recorded air temperature, wind direction and velocity, precipitation, and solar radiation. Additionally, an automated camera recorded images of the lake inlet to document changes in the inflow stream and the occurrence of surface sediment plumes. Vertical water column profiles reveal that Linnévatnet is dominated by overflow density currents near the lake inlet, while underflow density currents were detected distal to the inlet. Delta turbidity flows were also detected. The sediment plumes fluctuated in great breadth and depth, though they could not be directly constrained to individual meteorological conditions. As a second objective, a baseline study of the Linnévatnet thermal regime was performed. Lake temperatures reached 6.5ºC, surpassing previously speculated temperatures for this High Arctic meltwater lake.
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