This powerful eruption occurred in Deception Island 3,980 years ago and not 8,300 as previously thought.
A large volcanic eruption shook Deception Island, in Antarctica, 3,980 years ago, and not 8,300, as it was previously thought, according to an international study published in Scientific Reports, in which researchers from the Institute of Earth Sciences, Jaume Almera, have participated.
This event was the largest eruption in the austral continent during the Holocene, and was comparable in volume of ejected rock to the Tambora volcano eruption in 1815. The eruption formed the caldera of the volcano, one of the most active in Antarctica, with more than 20 eruptions registered in the last 200 years.
A depression between 8 and 10 kilometers in diameter was formed, which is what today gives to Deception Island its particular horseshoe shape
According to the age published in this new study, a volcanic eruption caldera collapse type took place 3980 years ago. The emptying of the magmatic chamber, the zone of magma accumulation that fuelled the eruption, during this violent eruptive event caused a sudden pressure drop which in turn caused the collapse of the upper part of the volcano. As a result, a depression between 8 and 10 kilometers in diameter was formed, which is what today gives to Deception Island its particular horseshoe shape.
The caldera collapse would have caused a seismic event of great magnitude whose trace was recorded in the sediments accumulated in the lakes' bottom of Livingstone Island. The lacustrine sediment cores were recovered during the Antarctic campaigns of the HOLOANTAR project, between 2012 and 2014.
The exact date of the eruption was obtained using different geochemical, petrological and paleolimnological techniques
The exact date of the eruption was obtained using different geochemical, petrological and paleolimnological techniques applied on the sediment cores from 4 lakes of the Byers Peninsula from Livingston island. These sedimentary records contained several direct and indirect pieces of evidence of the volcanic event that occurred in Deception Island.
One of the challenges that faced this study was to characterize the origin of the ashes produced during the volcanic eruption. For that, pressure and temperature conditions of the magmas that originated this eruption were calculated using the ashes present in the sediment cores.
The study also estimates that the eruption had a Volcanic Explosive Index (VEI) around 6 which possibly makes it the largest known Holocene eruptive episode in the Antarctic continent. As suggested by this study, this eruption could have had significant climatic and ecological impacts in a large area of the southern region, although more studies and new data are needed to precisely characterize what the real effects on the climate of this large eruptive event.