Can XRF scanner data be applied as grain-size proxy? - Clues from north-eastern Siberian arctic lake sediments

• Main Authors: Biskaborn, Boris, Funk, Christiane, Herzschuh, Ulrike, Bolshiyanov, D., Vakhrameeva, P., Diekmann, Bernhard
• Format: Conference Object
• Language: unknown
• Published: 2010
• Subjects: Arctic; lena river; permafrost; Thermokarst; Siberia
• Online Access: https://epic.awi.de/id/eprint/22780/; https://hdl.handle.net/10013/epic.35477

During a collaborative German-Russian helicopter expedition an ecological and limnogeological survey of 14 thermokarst lakes was undertaken along a north-south transect (73°-69°N) along the western side of the lower Lena river (HERZSCHUH et al. 2009). The aim of research project is to reconstruct the Holocene palaeoenvironmental history of north-east Siberia, one of earths most extreme continental climate settings in the northern-hemispheric periglacial realm. Here we present findings from the study of El'gene Kyuele (71°18,04' N, 125°34,15' E), situated in the middle part of the transect, about 50 km north of the present treeline. The lake has a length of 2.9 km and a width of 0.5 km with a maximum water depth >5m. It is built by thermokarst processes of the surrounded deeply loesslike sediments (Yedoma). The elongated shape corresponding to the regional geological structure of the bedrock also indicates a tectonic component influencing the thermokarst lake genesis. The study is devoted to the reconstruction of the depositional palaeoenvironment in a typical thermokarst permafrost setting. What is the sediment source and how much is the thermokarst erosion influencing the sedimento-logical regime? To give an answer to this question geochemical and grain-size studies were conducted on sediment core PG1975-1 retrieved in the central part of the lake using a hammer-modified gravity corer. The core is 136 cm long with a basal age of 6792 ± 30 14C years BP.Downcore elemental composition were obtained by X-Ray Fluorescence Analysis (XRF) using the Avaatech XRF Core Scanner at AWI Bremerhaven. Grain-size has been analysed using a Laser Diffraction Particle Analyser. Additionally smear slides provide qualitative insight into the sediment features suggesting a possibly correlation of grain-size to Sr/Rb ratio. Geostatistical factor analysis of the XRF data reveal Sr/Rb showing a significant proportion of the data variance. In this study we apply Sr/Rb ratio and Zr as grain-size proxies. A significant correlation of ...