A large volcanic eruption shook Deception Island 3,980 years ago
A large volcanic eruption shook Deception Island, in the Antarctica, 3,980 years ago instead of 8,300, as it was thought so far, according to an international study published in Scientific Reports. This event was the largest volcanic eruption in the continent during the Holocene (the last 11,700 years after the large glaciation of the Earth) and it was comparable in volume to the Tambora Volcano eruption in 1815. Also, the eruption created the caldera of the island volcano, one of the most active ones in the Antarctica, with more than twenty recorded eruptions over the last 200 years.
A large volcanic eruption shook Deception Island, in the Antarctica, 3,980 years ago instead of 8,300, as it was thought so far, according to an international study published in Scientific Reports. This event was the largest volcanic eruption in the continent during the Holocene (the last 11,700 years after the large glaciation of the Earth) and it was comparable in volume to the Tambora Volcano eruption in 1815. Also, the eruption created the caldera of the island volcano, one of the most active ones in the Antarctica, with more than twenty recorded eruptions over the last 200 years.
The study, whose first author is Dermot Antoniades, from Laval University, Canada, counts on the participation of researchers from the University of Barcelona, the Institute of Earth Sciences Jaume Almera (ICTJA-CSIC), the University of Salamanca, CREAF, the Research, Monitoring and Evaluation Center of the National Park in Sierra de Guadarrama, the University of Cambridge, and the Centro de Estudios Hidrográficos and the University of Leilcester.
3,980 years ago, according to the study, a caldera collapse large eruption occurred. The magma chamber emptying, the area of accumulation of magma that fed the eruption, during the violent eruption event, caused a severe decline of pressure and caused the collapse of the upper area of the volcano. As a result, a depression of about 8 and 10 km of diameter was created, which is the one that gives Deception Island its particular shape of horseshoe. The caldera collapse would have caused a large magnitude seismic event and its traces were registered in the sediment at the bottom of the lakes in Livingston Island.
These lacustrine sediments were recovered over the Antarctic campaigns in the HOLOANTAR project that were carried out between 2012 and 2014 and coordinated by Marc Oliva, at that time researcher at the Institute of Geography and Spatial Planning of the University of Lisbon and now Ramon y Cajal researcher at the UB, and co-author of this study.
To set the exact date of the eruption, researchers took and analysed, through geochemical, petrology and paleolimnology tehcniques, several samples of sediments from four lakes of the Byers Peninsula in Livingston. Researchers identified direct and indirect evidence of the volcanic episode that took place in Deception Island.
One of the challenges of the study was to determine the origins of the ashes that were formed during the eruption. To do so, they calculated the pressure and temperature coincidence of magma that the eruption generated out of the analysis of sample ashes. With this, they could estimate the depth of the origins of each sample and could specify whether they belonged to the same magma and the same eruption episode.
It is estimated that the dated eruption in the study had a Volcanic Explosivity Index (VEI) of 6, which probably makes it in the largest eruption episode of the Holocene known and dated so far in the Antarctic continent.
According to the study, this eruption could have had a climate and ecologic impact in a big area of the austral region, although more studies and new data are necessary to know its effects on climate.
This study is framed within the research dynamics promoted in polar and high-mountain areas by the research group Antartic, Arctic, Alpine Environments(ANTALP), with the support of the Agency for Management of University and Research Grants (AGAUR) of Generalitat de Catalunya.
Reference article
Antoniades, D.; Giralt, S.; Geyer, A.; Álvarez-Valero, A. M.; Pla-Rabes, S.; Granados, I.; Liu, E. J.; Toro, M.; Smellie, J. L., i Oliva, M. "The timing and widespread effects of the largest Holocene volcanic eruption in Antarctica". Scientific Reports, November 2018. Doi: 10.1038/s41598-018-35460-x