Last Interglacial Climate in Northern Sweden—Insights from a Speleothem Record

Continental records with absolute dates of the timing and progression of climatic conditions during the Last Interglacial (LIG) from northern Europe are rare. Speleothems from northern Europe have a large potential as archives for LIG environmental conditions since they were formed in sheltered environments and may be preserved beneath ice sheets. Here, we present δ¹³C and δ¹⁸O values from speleothem Kf-21, from Korallgrottan in Jämtland (northwest Sweden). Kf-21 is dated with five MC-ICPMS U-Th dates with errors smaller than ~1 ka. Kf-21 started forming at ~130.2 ka and the main growth phase with relatively constant growth rates lasted from 127.3 ka to 124.4 ka, after which calcite formation ceased. Both δ¹³C and δ¹⁸O show rapid shifts but also trends, with a range of values within their Holocene counterparts from Korallgrottan. Our results indicate an early onset of the LIG in northern Europe with ice-free conditions at ~130 ka. Higher growth rates combined with more negative δ¹⁸O values between ~127.3 and 126.8 ka, interpreted here as warmer and more humid conditions, as well as indications of a millennial-scale cold spell centered at 126.2 ka, resemble findings from speleothem records from other parts of Europe, highlighting that these were regional scale climatic patterns.