CHARACTERIZATION OF CLIMATIC INFLUENCES ON MODERN SEDIMENTATION IN AN ARCTIC LAKE, SVALBARD, NORWAY

Modern sedimentation in Linnevatnet was studied as part of the NSF-funded Svalbard REU Project to calibrate the lamination stratigraphy in the glacier-fed lake. Linnevatnet, located on the west coast of Spitsbergen is 6 km long (1 km wide). The lake receives melt water from the Linne glacier, located 8 km up valley. Sediment traps located at different locations and at different depth collected sediment in the lake from July 2003 to August 2004. Short sediment cores were also sampled in the summer of 2004 to help investigate recent sedimentation (past ca. 50 years). The focus of the investigation is to better understand climatic effects on yearly sedimentation, and to better characterize annual variation in the sediment record. Sediment traps were deployed at seven sites (each site having traps at varying depths), and over three time intervals, in order to facilitate further spatial and temporal understanding of sedimentation occurring in the lake. Sediment traps were retrieved in order to determine total sedimentation, micro stratigraphy and textural changes at each location. The sediment was sub-sampled and analyzed using a Coulter LS230 Particle Analyzer in order to characterize textural changes both temporally in each trap as well as spatially throughout the lake. Short cores were likewise sampled for grain size analysis. Sedimentation rates calculated from the recovered year-long sediment traps suggested rates as high as 13 mm of deposition over the past year in the most proximal traps. This sedimentation rate is nearly an order of magnitude higher than what was proposed from earlier work that calculated an average rate of sedimentation based on thickness of lacustrine sediments in the lake. Seasonal traps illustrate that as much 26% of yearly deposition occurred in a two week span from July 27 to August 12, which is consistent with the suggestion that nearly all of the sedimentation in the lake occurs during the summer months. Weather events (rain and solar insolation) were seen to increase both the average grain sizes of the sediments and rates of sedimentation proportional to the intensity and duration of the weather event.