Sediment dynamics of the pro-glacial Tarfalajaure, Kebnekaise.

The sensitive response of glaciers to climate change can be recorded in sediments, in glacier fed lakes. By studying sediments from pro-glacial lakes it is possible to determine how glaciers have reacted to past climate change and variability. Therefore, proglacial lake sediments cores can be used as proxy archives for climate and glacier activity reconstructions. The aim of this study is to detect any glacier signal in the lacustrine sediment cores from Tarfalajaure and seek for correlation with glacier processes and variations recorded in the past literature. Sediment cores were retrieved from the deepest part (52 m) of Tarfalajaure (65°55’25”,18°35’23”) in September 2016. Tarfalajaure is situated within the Swedish part of the Scandinavian Caledonides, in the Kebnekaise Mountains, northern Sweden. There are four glaciers draining into Tarfalajaure, Kebnepakteglaciären (the closest and largest one), Sydöstra Kaskasatjåkkaglaciären, Sydöstra Kaskasapakteglaciären and SydvästraKaskasatjåkkaglaciären. It is assumed that the variations of the minerogenic input and sediment characteristics in the cores over time reflect variations in glacier activity or changes in the proglacial environment. XRF measurements (Ti, Si, K, Fe, Ca, Mn/Fe, Zr/Rb, Ca/Ti,Fe/Ti, Si/Ti, K/Ca and K/Ti), magnetic susceptibility, grain-size analysis and radiocarbon dating have been used to detect variations in the sediment core. Comparisons have been made with results from other studies of glacier activity in northern Scandinavia, and with reconstructions of temperature variation during the last millennia. The results indicate several periods of glacieradvances which were also identified in other studies. These advances occurred around 25 cal BP, between 300 and 375, 1000 and 1150 cal BP, and around 700 – 800, 1900, and 2200 –2275 cal BP