| Summary: | Modern sedimentation in Lake Linné was studied as part of the NSF-funded Svalbard REU Project to calibrate the lamination stratigraphy in the glacier-fed lake. Lake Linné, located on the west coast of Spitsbergen, receives melt water from the Linné glacier, located 8 km up valley. 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 five sites (each site having traps at varying depths), from July 2003 to August 2004, in order to facilitate spatial and temporal understanding of sedimentation occurring in the lake. The collected 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. Sedimentation rates calculated from the recovered yearlong sediment traps ranged from 277 to 28 mg/cm2/yr (1.5 to 0.15 mm/yr) from the most proximal to distal sites respectively. These sedimentation rates compare well to calculated average rates of sedimentation based on thickness of lacustrine sediment in the lake. Changes in grain size recorded in the sediment traps throughout the year demonstrate a strong peak in grain size associated with a spring melt event. These melt-out deposits are substantially coarser (median grain size = 53 µm) than any other sediment deposited during the year, including deposits associated with a high precipitation and discharge event (median grain size < 16 µm). This suggests that the spring melt sediment is deposited by different mechanism, most likely overland flow during the spring melt. Weather events (rain and solar insolation) affected the grain size of sediment deposited proximally in the lake; median grain size is strongly correlated to discharge from the inlet stream in the late summer.
|
|---|