Antarctic Glass Shards Reveal Clues to Massive New Zealand Volcanic Eruption

Around 1,800 years ago, New Zealand’s Taupō volcano unleashed one of the most powerful eruptions witnessed on Earth in the last 5,000 years. Its tremendous force hurled glass fragments all the way to Antarctica. This spectacular event has been the subject of a heated debate among scientists, each seeking to pinpoint the precise year of this colossal eruption. Now, recent discoveries of ancient volcanic debris buried in Antarctic ice promise to bring this debate to an end.

The Taupō eruption, which occurred around A.D. 232, rocked the Southern Hemisphere, sending volcanic fallout as far as Antarctica. However, the timing of this event has been a topic of contention for decades. Radiocarbon dating of trees killed by the eruption initially suggested the year 232, but skepticism persisted, with some experts suggesting the eruption might have happened up to two centuries later.

Researchers embarked on an expedition to West Antarctica in search of Taupō debris, and their efforts bore fruit when they extracted ice cores from a depth of 915 feet (279 meters) below the surface. Their discovery of seven unique volcanic glass shards concealed within these ice cores strongly supports the A.D. 232 date for the eruption. As Stephen Piva, the lead author of the study, explained, “Our discovery of seven geochemically unique volcanic glass shards buried deep within an ice core confirms the likely timing of the eruption in late summer/early autumn in the year 232.”

To ascertain the veracity of their findings, researchers conducted an in-depth analysis of the chemical composition of the glass shards. Six of these shards were definitively linked to the Taupō eruption, while the seventh was associated with an earlier eruption of the same volcano, known as the Ōruanui eruption, which took place approximately 25,500 years ago. The fact that all seven shards were discovered at similar depths in the ice suggests that the Ōruanui eruption’s glass fragments were buried near the volcano and later propelled into the atmosphere during the Taupō eruption. High-altitude winds then carried the volcanic debris, dispersing it across New Zealand’s North Island, the southwest Pacific Ocean, and ultimately, West Antarctica, a staggering 3,100 miles (5,000 kilometers) away.

The timing of the shards’ arrival in Antarctica was determined by examining the surrounding ice layers. This groundbreaking discovery of glass fragments from two separate eruptions of the same volcano serves as undeniable evidence of the Taupō eruption’s timing and the immense power of these volcanic events. The fact that these glass shards traveled such great distances through the upper atmosphere underscores the extraordinary magnitude of these eruptions.

The Taupō eruption, which persisted for several days to weeks, culminated in a spectacularly energetic lava explosion that devastated an area spanning 7,700 square miles (20,000 square kilometers). Given the immense scale of this event, the question arises as to why it has been so challenging to detect and validate in Antarctic ice cores, a conundrum that continues to intrigue researchers.

In summary, the discovery of Antarctic glass shards from the Taupō eruption provides a definitive answer to the long-standing debate over the eruption’s timing and sheds light on the astonishing power of volcanic events that occurred nearly two millennia ago.