Alkenone temperature data from three Holocene lake sediment sequences on Svalbard

These data encompass three temperature Arctic temperature reconstructions that cover the entire Holocene epoch – the past 11 700 years. Temperatures were inferred using the UK37 alkenone unsaturation index after doi:10.1016/S0146-6380(86)80001-8, and the Group 1 phylotype calibration by doi:10.1016/j.gca.2015.10.031 following chemotaxonomic identification using the RIK indices after doi:10.1016/j.gca.2016.02.019. We report samples that derives from lake sediment cores taken in 2014 from three closely-spaced lakes on Arctic Svalbard (79.5°N:11°E): Gjøavatnet (n=98), Hajeren (n=67) and Hakluyt (n=90). Alkenones were isolated following ASE extraction and silica gel flash chromatography. Alkenone ratios were determined using Gas Chromatograph Ionization (GC-FID). All analytical analyses were carried out at Lamont Doherty Earth Observatory (LDEO) of Columbia University in 2016-2017. Alkenone temperatures are expressed as deviations from the 1850-1900 AD Pre-Industrial average as detailed in the Supplementary of doi:10.1029/2019GL084384. Core chronologies are based on 14C dating and were generated by previous workers – based on these existing age-depth relations, each of the presented records resolves sub-centennial changes. These temperature reconstructions were generated to place on-going Arctic warming in a long-term context. Our findings show that reconstructed temperatures exceeded instrumental observations and 21st century projections during the Early Holocene period around 10 000 years ago.