Hugo Jomier

Sediments dynamics of pro-glacial Tarfalajaure, Kebnekaise

Datum, tid och plats: Torsdag den 14 juni, kl 10:00 i Ahlmannsalen
Handledare: Gunhild Rosqvist
Examinator: Benedict Reinardy
Masterprogram i glaciologi och polarmiljöer, 120 hp
Examensarbete i naturgeografi och kvartärgeologi, 60 credits
Presentationen är på engelska

The Arctic is a key region in current global warming because it is warming faster than anywhere else on the planet in the last decades. The retreat of most of the glaciers is one of the results of this global warming, especially in the arctic regions since the end of the Little Ice Age. It is important to understand what happened in the past, the changes that specific regions have undergone to be able to predict more precisely, what could happen in the future. Every glacier is different and thus react differently to any change in weather and climate. The sensitive response from glaciers to climate can affect the minerogenic production from the glacier, and can be recorded in lacustrine sediments downstream in glacier fed lakes. By studying sediments from pro-glacial lakes in front of glaciers, it is possible to read how glaciers have reacted to certain events and what are their past variability through time. Therefore, proglacial lake sediments core can be used as proxy archives for climate and glacier activity reconstructions. The aim of this study is to see if glacier signal can be seen within the lacustrine sediments of Tarfalajaure and seek for correlation with glacier processes and variations. In 2016, a sediment core has been retrieved from the deepest part of Tarfalajaure (65°55’25”, 18°35’23”), which is situated within the Swedish part of the Scandinavian Caledonides, in the Kebnekaise Mountains, northern Sweden. Tarfalajaure is the proglacial lake of Kebnepakteglaciären (and three other glaciers), and thanks to its vicinity to the glacier, there were high chances to find a time-record of the variations of the minerogenic input coming from the glacier within its lacustrine sediments. XRF measurements (Ti, Si, K, Fe, Ca, Mn/Fe, Zr/Rb, Ca/Ti, Fe/Ti, Si/Ti, K/Ca and K/Ti) and magnetic susceptibility have been used to detect variations in the sediment core. Comparisons have been made with other publications about glacier activity in northern Scandinavia, and reconstructions of temperature in the last millennia. Therefore, the results for major periods of glacier advances supported by the current literature might have occurred around 25 cal BP, between 300 and 375 and 1000 and 1150 cal BP, around 700 – 800, 1900, and 2200 – 2275 cal BP.