Mg/Ca paleotemperature reconstruction of Atlantic Water advected to the European subarctic and arctic margins in the past 14.000 cal yr B.P.

• Main Authors: Aagaard-Sørensen, Steffen, Husum, Katrine, Hald, Morten, Marchitto, Tom, Werner, Kirstin, Spielhagen, Robert
• Format: Conference Object
• Language: unknown
• Published: 2011
• Subjects: Andfjorden; Arctic; Norway; Foraminifera*; north atlantic current; North Atlantic; North Norway; Sea ice; Subarctic; Spitsbergen
• Online Access: https://oceanrep.geomar.de/id/eprint/11912/; http://www.geogr.msu.ru/structure/labs/notl/nauchd/downloads/Abstracts_2011_APEX_Longyearbyen.pdf

Foraminiferal Mg/Ca-ratios have proven to be valuable proxies for reconstructing past water temperatures and salinities especially in subtropical to tropical regions. However, recent studies have expanded the temperature range of the proxy to include subarctic and arctic environments. In this study we aim to reconstruct the temperatures of the inflowing Atlantic Water mass on the European arctic and subarctic margins from late glacial to the present using Mg/Ca-ratios measured on planktic and benthic foraminiferal tests. The Atlantic Water is carried towards the Arctic by the North Atlantic Current and its meriodinal extension the West Spitsbergen Current. Both currents are important components of the meridional overturning circulation system of the North Atlantic. Furthermore, these currents contribute to the relatively milder climate along their paths. The subarctic paleorecord is based on two adjacent cores from ca. 500 m water depth in the Andfjorden, North Norway covering an Allerød - present sequence constrained by 15 AMS datings. SiZer analysis indicates variable chilled bottom water temperatures during Allerød and Younger Dryas, before a significant multistep temperature increase mark the onset of the Holocene. Stable relatively high temperatures prevail throughout the Holocene with a significant but modest decline at around 3.500 cal yr B.P. The arctic paleorecord is based a core from ca. 1500 m water depth on the West Spitsbergen slope. The core covers an Allerød - present sequence constrained by 13 AMS datings. SiZer analysis indicates no significant sea surface temperatures (SSTs) during the Late Glacial/Holocene boundary presumably linked to prevailing severe sea ice conditions and melt water influence in the area. Significant SST decline is observed from the early Holocene to ca. 6.000 cal yr B.P. SST remain remains low and stable until ca. 3000 cal yr B.P. after which a significant temperature increase initiates and continues toward the present.