Fe 2+ in ice cores as a new potential proxy to detect past volcanic eruptions

• Published in: Science of The Total Environment
• Main Authors: Burgay F., Erhardt T., Lunga D. D., Jensen C. M., Spolaor A., Vallelonga P., Fischer H., Barbante C.
• Other Authors: Burgay, F., Erhardt, T., Lunga, D. D., Jensen, C. M., Spolaor, A., Vallelonga, P., Fischer, H., Barbante, C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Chemiluminescence; Continuous flow analysi; Greenland; Iron speciation; Volcano; Settore CHIM/01 - Chimica Analitica; Greenland ice core; ice core
• Online Access: http://hdl.handle.net/10278/3724402; https://doi.org/10.1016/j.scitotenv.2018.11.075

Volcanic eruptions are widely used in ice core science to date or synchronize ice cores. Volcanoes emit large amounts of SO 2 that is subsequently converted in the atmosphere into sulfuric acid/sulphate. Its discrete and continuous quantification is currently used to determine the ice layers impacted by volcanic emissions, but available high-resolution sulphate quantification methods in ice core (Continuous Flow Analysis (CFA)) struggle with insufficient sensitivity. Here, we present a new high-resolution CFA chemiluminescence method for the continuous determination of Fe 2+ species in ice cores that shows clear Fe 2+ peaks concurrent with volcanic sulphate peaks in the ice core record. The method, applied on a Greenland ice core, correctly identifies all volcanic eruptions from between 1588 to 1611 and from 1777 to 1850. The method has a detection limit of ∽5 pg g −1 and a quadratic polynomial calibration range of up to at least 1760 pg g −1 . Our results show that Fe 2+ is a suitable proxy for identifying past volcanic events.