Multi-proxy evidence of unprecedented hydroclimatic change in a high Arctic proglacial lake:Linnévatnet, Svalbard

• Published in: Arctic, Antarctic, and Alpine Research
• Main Authors: Lapointe, Francois, Retelle, Michael, Bradley, Raymond S., Farnsworth, Wesley R., Støren, Eivind, Cook, Timothy, Rosario, Josiane
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: climate; grain size; Linnébreen; Linnévatnet; micro-X-ray fluorescence; sediment provenance; Arctic; Linnéelva; Lomonosovfonna; Svalbard; Antarctic and Alpine Research; glacier; Magnetic susceptibility; north atlantic current; North Atlantic; Sea ice; Spitsbergen
• Online Access: https://researchprofiles.ku.dk/da/publications/ee74664d-4424-4a7e-b08a-e9b6edd55b9b; https://doi.org/10.1080/15230430.2023.2223403; https://curis.ku.dk/ws/files/361458278/Multi_proxy_evidence_of_unprecedented_hydroclimatic_change_in_a_high_Arctic_proglacial_lake_Linn_vatnet_Svalbard.pdf

Svalbard is at the forefront of sea ice, marine, and terrestrial environmental change in the Arctic and so can be viewed as an example of what may be expected in other high latitude regions influenced by the North Atlantic Current. However, there are few highly resolved (subdecadal) paleoclimate records from this area that provide a long-term perspective on recent climatic changes. Here, we investigate a new composite sedimentary sequence from Linnévatnet, western Spitsbergen, spanning the last ~2,000 years. The chronology of this new composite laminated sequence is supported by four radiometric dates. Prior to conducting paleoclimate investigations on these lake sediments, we investigated the sediment sources entering Linnévatnet. Sediment samples collected around the lake’s watershed indicate that the main sediment sources come from the eastern carbonate valley wall as well as Linnéelva, the main river system. Micro-X-ray fluorescence (µ-XRF) results indicate that calcium is the largest component of sediment delivered to the delta-proximal basin, where the sedimentary record was collected. Percentage organics deduced from loss-on-ignition measurements reveal an antiphased relationship with calcium and magnetic susceptibility, implying that the sediment loading at the core site is largely modulated by the alternation of calcium derived from carbonates of the eastern flanks of the valley and by coal-bearing sandstone from Linnéelva, derived from the main river inflow that drains the central valley. Linnéelva is mainly fed by snow and glacier meltwaters from Linnébreen, the small valley glacier now located 7 km south of Linnévatnet. Because Linnébreen is underlain by coal-bearing sandstone, organic content in Linnévatnet lake sediments can be used as an indicator of glacier activity. Annually resolved parameters—that is, calcium and grain size—were found to be strongly correlated to temperature inferred from nearby Lomonosovfonna δ 18 O ice record as well as the wider reconstructed Northern Hemisphere winter ...