Friday meant re-grouping with the lake team (Mike, Dion, and Helena) on Linne to grab a few more cores for Helena's thesis. Our hope for the next two days was to core at sites near shoreline solufluction stations where Helena had taken sediment samples in order to trace the sediments from each of these unique locations to the sedimentary record in the lake close to the source. From there, Helena hopes to be able to quantify the contributions of such sediment sources to cores from other locations in the lake…but, don't just take my word for it. Earlier, I'd made an offer to anyone in either of the courses of a half a bar of chocolate for them to submit a paragraph summary of their thesis objective and Helena just won the prize. So, in her own words, here is a preliminary thesis proposal/description of her work here in Svalbard…

Today's spotlight researcher, Helena Tiedmann
Today's spotlight researcher, Helena Tiedmann

"The goal of my project is to better understand sources of sediment in Lake Linné, specifically areas of marine sediments that border the lake. In areas like Svalbard where there is permafrost, it is common to have lobes of solifluction on the land surface. Solifluction refers to the slow deformation and movement of the top layer of sediment as it freezes and thaws between seasons above the permafrost. Much of the shore of Lake Linné is undergoing solifluction, with large lobes of sediment slowly flowing down slope into the lake. While the principle source of sediment into the lake is the runoff stream from the Linné Glacier up valley, it is suspected that these solifluction lobes are still significant sediment contributors. To understand this input, I am undertaking a range of methods in the field and in the lab. First, I am mapping the lakeshore to identify where this solifluction is occurring and attempting to rate how actively sediments are being transported. Second, I am placing short-term sediment traps just offshore near these active lobes to try to catch sediment entering the lake. Third, I am taking cores from the bottom of the lake and samples from the areas around the lakeshore to take home for analysis. Finally, I am observing climate data and taking periodic measurements of temperature, conductivity and turbidity at different depths in various locations in the lake, especially after significant weather events. Once I am back at school I will compare the geochemistry and mineralogy of the shore samples, the lake core samples, and the samples from my short-term traps to try to identify how much sediment from these lobes is entering the lake. With relation to the overall REU, the project goals have been to relate climatic conditions to sedimentation patterns in the lake, with a primary focus on the river and glacier sources. By examining secondary sediment sources, hopefully we can better understand some of the remaining unknown factors surrounding sedimentation and climate."

One of Helena's shallow, coast-proximal cores.
One of Helena's shallow, coast-proximal cores. Note the gravity/percussion corer still attached. The first brass ring is a simple weight to aid the core entering the sediments while the second is attached to a separate line and moves up and down the threaded rod to hammer the tubing into the mud.

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