Prefacing unexplored archives from Central Andean surface-to-bedrock ice cores through a multifaceted investigation of regional firn and ice core glaciochemistry

• Published in: Journal of Glaciology
• Main Authors: Heather M. Clifford, Mariusz Potocki, Charles Rodda, Daniel Dixon, Sean Birkel, Michael Handley, Elena Korotkikh, Douglas Introne, Franciele Schwanck, Flavia A. Tavares, Ronaldo T. Bernardo, Filipe G. L. Lindau, Oscar Vilca Gomez, Harrison Jara-Infantes, Victor Bustínza Urviola, L. Baker Perry, Jonathan Maurer, Anton Seimon, Margit Schwikowski, Gino Casassa, Shugui Hou, Andrei V. Kurbatov, Kimberley R. Miner, Jefferson C. Simões, Paul A. Mayewski
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2023
• Subjects: Climate change; glaciological instruments and methods; ice chemistry; ice core; mountain glaciers; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Core Mountain; Ice cap; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2022.91; https://doaj.org/article/13a615f4cac4472aa5496c671e105092

Shallow firn cores, in addition to a near-basal ice core, were recovered in 2018 from the Quelccaya ice cap (5470 m a.s.l) in the Cordillera Vilcanota, Peru, and in 2017 from the Nevado Illimani glacier (6350 m a.s.l) in the Cordillera Real, Bolivia. The two sites are ~450 km apart. Despite meltwater percolation resulting from warming, particle-based trace element records (e.g. Fe, Mg, K) in the Quelccaya and Illimani shallow cores retain well-preserved signals. The firn core chronologies, established independently by annual layer counting, show a convincing overlap indicating the two records contain comparable signals and therefore capture similar regional scale climatology. Trace element records at a ~1–4 cm resolution provide past records of anthropogenic emissions, dust sources, volcanic emissions, evaporite salts and marine-sourced air masses. Using novel ultra-high-resolution (120 μm) laser technology, we identify annual layer thicknesses ranging from 0.3 to 0.8 cm in a section of 2000-year-old radiocarbon-dated near-basal ice which compared to the previous annual layer estimates suggests that Quelccaya ice cores drilled to bedrock may be older than previously suggested by depth-age models. With the information collected from this study in combination with past studies, we emphasize the importance of collecting new surface-to-bedrock ice cores from at least the Quelccaya ice cap, in particular, due to its projected disappearance as soon as the 2050s.