| Summary: | Abstract: In July 2009, we recovered a varved sediment core from 35 m in the deep main basin of Linnévatnet, a high Arctic glacial lake in Svalbard. Arctic lakes are key locations for studying climate records because the Arctic is highly sensitive to climate change and because varves reflect seasonal and annual sedimentation rates. Previous research in Linnévatnet has focused primarily on the proximal basin near the Linnéelva (Linné River) inlet where it is difficult to distinguish annual sediment layers from event-based layers. The lake core analysis will therefore contribute to our understanding of the sediment stratigraphy in the deep main basin where varves reflect annual sedimentation. Core IC09.1 is 39.8 cm long and contains 1154 ± 71 couplets, which we measured in Photoshop using high-resolution (4800 dpi) scanned images of thin sections. The varves range in thickness from 0.06 mm to 2.60 mm with a mean thickness of 0.34 mm. To make a proxy climate record, we compared varve thickness to summer temperature, summer precipitation, winter precipitation, and glacier mass balance from the instrumental record. Summer temperature and summer precipitation show a statistically significant positive correlation with varve thickness, though with a low coefficient of determination (r2). We used thickness and a regression equation to estimate climate pre-dating the instrumental record. If higher summer temperatures and increased precipitation are related to thicker varves, then summer temperature and precipitation have been greater in the 20th Century than in the past 1,000 years, and climate change in the 20th Century has been greater than during the Little Ice Age and the Medieval Warm Period.
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