In an East Antarctic ice core from the Mount Brown South site, scientists have discovered microscopic fragments of volcanic glass—known as cryptotephra—which were carried long distances by the wind and preserved within the coastal snow and ice.
The study, published on June 19, 2026, by the Australian Antarctic Program Partnership, was conducted by an international team led by the University of Tasmania. Published in the journal Climate of the Past, the research presents a pilot analysis of a nearly 300-meter core drilled between 2017 and 2018. Focusing on the satellite era from 1979 to 2017, the scientists confirmed that even ash particles invisible to the naked eye can travel thousands of kilometers and remain trapped in the Antarctic ice.
Lead author Dr. Meg Harlan noted that the core provides a new window into Southern Hemisphere volcanism, atmospheric circulation, and the climatic impact of eruptions. Two layers of cryptotephra were successfully linked to specific events: the 1985 eruption of Mount Erebus on Antarctica's Ross Island and the powerful 1991 explosion of Chile’s Cerro Hudson volcano. The latter represents the first confirmed instance of ash from this particular eruption being identified in Antarctic ice.
Finding such traces is often compared to looking for a "needle in a haystack," as volcanic layers in Antarctic cores are extremely rare and scattered across tens or hundreds of meters of ice. The team developed a new method that combines atmospheric transport models with chemical signatures found within the ice itself. This approach allowed for targeted sampling and significantly reduced the overall workload.
The results demonstrate that ash transport pathways are more complex than previously thought, with material arriving from South America as well as nearby Antarctic sources. These findings help to more accurately date ice archives by distinguishing between different volcanic signals, leading to a better understanding of how volcanic activity influenced past climate fluctuations.
The Mount Brown South core is located in a region where South Indian Ocean air currents deposit material from various latitudes, making it a valuable repository of data on Southern Hemisphere volcanism. Further research could significantly expand the database of southern eruptions and improve climate models.
A better understanding of how and where traces of ancient eruptions are preserved allows for a more accurate assessment of their impact on climate archives.
