Ice Cores Extracted from Polar Regions Hold Secret to Large Volcanic Eruptions Beyond 2,500 Years

An ice core that was detected to have originated 60,000 years ago was discovered to have signs of ancient volcanic eruptions. These explosions trace back to the last major ice age that covered the planet.

Among the largest volcanic eruptions found from the ice were 25 explosions larger than Earth experienced for the last 2,500 years.

Ice Cores and Ancient Volcanic Eruptions

(Photo: NEEM / University of Copenhagen / Niels Bohr Institute)
Anders Svensson inspecting an icecore in Greenland

Experts investigating ice cores in both polar regions found traces of massive volcanic eruptions during ancient times. These cores were extracted from Greenland, where 1,113 eruptions were listed, and Antarctica, giving evidence of 737 eruptions.

Among the previous volcanic eruptions, approximately 85 events left a distinctive mark that signifies their intensity compared to the rest.

The study on the volcanic eruption records embedded in these ice cores was made possible through the help of sulfuric acid deposits discharged during the outbursts.

Different categories such as levels of these deposits could help experts determine the particular volcanoes responsible for the explosions and the rate of extremities they demonstrated during the eruptions.

University of Copenhagen Niels Bohr Institute expert and co-author of the study Anders Svensson explained in a Science Alert report that the process of reconstructing the ancient volcanic eruptions could be possible through unearthing ice cores, as they also present several factors that are useful for the investigation of the particular geological activities in the past.

Overly-large eruptions commonly produce sulfuric acid that ejects so high to the sky that the compounds reach the upper regions of the atmosphere. When this happens, the sulfuric acids tend to return to the surface but are scattered throughout parts of the globe.

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Sulfuric Acids Trapped in Ice Core Key to Records of Volcanic Eruptions Larger Than We Thought

Due to atmospheric aspects, most of the large eruptions are likely to displace their sulfuric acid emissions the most in polar regions, including Greenland and Antarctica. The amount of the sulfuric acid would then keep the data from the event, even after thousands of years have already passed.

The team utilized many geological apparatus to collect measurements and data from the eruption clues embedded in the polar hemispheres, including the Volcanic Explosivity Index or VEI.

The VEI system can curate scales from the intensity of volcanic eruptions and results in one being the lowest, or eight being the highest. In the study, there were 69 explosions that surpassed the intensity of the Tambora eruption, which is measured at VEI 7.

VEI 7 from the massive explosion exhibited by Mount Tambora in Indonesia is so strong that it covered the sunlight from reaching the planet's surface and initiated an abnormal cooling of the global climate temperature.

Synchronizing Ice cores extracted from the polar regions commonly present the most accurate dating and information about the previous volcanic eruption in history, as shown in their previous study over a 25,000-year volcanic eruptions record published in the journal Nature.

VEI 7 eruptions only occur once or twice every thousand years. VEI 8, on the other hand, is rare and shows up in intervals of hundreds or thousands of years.

The new study of a 60,000-year timeline of eruptions was published in the journal Climate of the Past, titled "Magnitude, frequency and climate forcing of global volcanism during the last glacial period as seen in Greenland and Antarctic ice cores (60-9 ka)."