Fonte: X/@THERA_4ever
Nearly 2,000 years ago, a volcano erupted with a lot of violence on aisland north of New Zealand. Now, scientists have unearthed six glass fragments attributable to the heat of the explosion, launched 5,000 kilometers to the South where they remained buried under 280 meters of Antarctic ice for about 2,000 years.
And seventh fragmentformed by a previous eruption of the same volcano, helped the team pinpoint their precise origins, helping to confirm the timing of the explosive event.
The environmental scientist Stephen Pivalead author of the study and PhD student at the Transport Link-Victoria University of Wellington, explained as follows: “Combined, the seven fragments provide a unique and undeniable double fingerprint of the Taupō volcano as the source.”
Il Volcano Taupo it has been active for about 300,000 years, but the timing of its most recent major eruption, one of the largest and most violent in the past 5,000 years, has been difficult to pin down. So Piva and colleagues turned to a 764 meter long ice ‘core’, extracted from Ross Ice Sheet in West Antarctica and filled with approximately 83,000 years of climate information. At a depth of 279 meters the researchers found seven fragments of glass approximately 10-20 microns long and facts of mineral rhyolites similar to granite.
Their geochemical composition matched other samples of the Taupō eruption, collected in New Zealand. In particular, one of the fragments stood out, and it was a match for volcanic glass produced by the previous Ōruanui supereruption of Taupō volcano, which occurred 25,600 years ago. The Ōruanui glassbeing centuries older but made of the same material, was probably unearthed by the Taupō volcano and ejected into the stratosphere along with newly formed glass fragments from the 230 AD eruption