Mid-to Late Holocene East Antarctic ice-core tephrochronology: Implications for reconstructing volcanic eruptions and assessing their climatic impacts over the last 5,500 years

• Published in: Quaternary Science Reviews
• Main Authors: Abbott, Peter M., McConnell, Joseph R., Chellman, Nathan J., Kipfstuhl, Sepp, Hörhold, Maria, Freitag, Johannes, Cook, Eliza, Hutchison, William, Sigl, Michael
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2024
• Subjects: 530 Physics; 540 Chemistry; 550 Earth sciences & geology; Antarc*; Antarctic; Antarctica; East Antarctica; ice core; South Sandwich Islands; South Shetland Islands; Victoria Land
• Online Access: https://boris.unibe.ch/196390/1/Pub_THERA_29_Abbott2024_QSR.pdf; https://boris.unibe.ch/196390/

Ice cores are powerful archives for reconstructing volcanism as they contain both soluble (i.e. aerosols) and insoluble (i.e. tephra) products of volcanic eruptions and for more recent periods have high-precision annually resolved chronologies. The identification and geochemical analysis of cryptotephra in these cores can provide their volcanic source and latitude of injection, complementing records of sulphur injections from volcanic eruptions developed using continuous flow ice-core analysis. Here, we aim to improve the volcanic record for the Southern Hemisphere using a sampling strategy for cryptotephra identification based on coeval deposition of sulphate and microparticles in ice cores from the interior of East Antarctica covering the Mid-to Late Holocene. In total, 15 cryptotephras and one visible horizon were identified and geochemically characterised. Through comparisons to proximal deposits a range of possible sources were isolated for these horizons including the South Sandwich Islands, South Shetland Islands, Victoria Land (Antarctica) and South America. This new tephra framework contributes to the volcanic history of the region by extending the known geographical range of tephra deposition for previously identified events and providing a potential indication of phases of eruptive activity from key sources. Using the tephra-based source attributions and comparison of the timing of the events to a database of sulphur injections from Holocene volcanic eruptions it is possible to refine injection latitudes for some events, which can lead to improved estimates of their radiative forcing potential. The relatively low magnitude of the volcanic stratospheric sulphur injections related to the events in the tephra framework indicates they would have had a limited impact on Southern Hemisphere climate. Further work is required to improve source attributions for some events and/or to determine the magnitude of sulphur injections for individual events during years when coeval eruptions occurred. One limitation ...