About 2,000 years ago, Rome was flourishing, unaware that a volcanic eruption from New Zealand’s North Island would potentially darken their skies. Scientists have recently discovered evidence of this cataclysmic event—six glass fragments, byproducts of the intense volcanic heat, found beneath 280 meters of Antarctic ice.
These fragments traveled an incredible 5,000 kilometers (3,100 miles) from their source. Additionally, a seventh shard, from a prior eruption of the same volcano, helped identify the volcano and confirm the eruption’s timeframe.
The Taupō volcano has an active history spanning 300,000 years. Despite its significant last eruption being one of Earth’s most explosive in the past 5,000 years, its precise date remained elusive. Historical descriptions hinted at a timeline, but inconsistencies with geological evidence brought more questions than answers.
Usually, volcanic eruptions are dated using sulfur deposits in ice cores. Such cores from both Antarctica and Greenland indicated that the Taupō eruption probably occurred around 230 CE.
However, as sulfur is released by multiple volcanoes globally, it doesn’t provide an exact timeframe. Radiocarbon dating of trees consumed by the volcanic flow suggested an eruption in late summer or autumn around 232 CE, but this date remained debated.
To refine this, Piva and his team turned to an impressive 764-meter-long ice core from West Antarctica, encapsulating 83,000 years of climatic data. Within this core, specifically at 279 meters deep, they found seven rhyolite-made glass shards.
The shards’ composition aligned with samples from the Taupō eruption found in New Zealand. Interestingly, one of these shards matched the glass from the Taupō volcano’s older Ōruanui supereruption from 25,600 years ago.
This distinctive combination, akin to a ‘double fingerprint’, heightened the team’s confidence in identifying the shards’ origin. The shards’ placement in the ice core dates them close to 230 CE.
The researchers theorize that the older Ōruanui glass, though created thousands of years prior, was thrust into the stratosphere alongside the 230 CE eruption’s newer shards. This suggests that the older material was likely dislodged and thrown into the air during the more recent eruption.
While the dating of ice cores isn’t flawless, this discovery strengthens the proposed age of the trees that were instantaneously annihilated by the scorching debris from the Taupō eruption.
The research not only offers a clearer understanding of the Taupō volcano’s eruption timeline but also underlines the vast, interconnected impact of geological events on our planet.