By Xinhua
Beijing : Evidence of a powerful volcano, which erupted under the ice sheet of West Antarctica around 325 BC and might still be active now, has been confirmed by British scientists, according to media reports Monday.
A layer of volcanic ash and glass shards frozen within an ice sheet in West Antarctica was identified in an article published in the journal Nature Geosciences by Hugh F. J. Corr and David G. Vaughan.
The volcanic eruption from beneath rated “severe” to “cataclysmic” on an international scale of volcanic force. It punched a massive breach in the ice sheet and spat out a plume some 12,000 meters (eight miles) into the sky.
“We believe this was the biggest eruption in Antarctica during the last 10,000 years,” Corr said.
Evidence for this comes from a British-American airborne geophysical survey in 2004-5 that used radar to delve deep under the ice sheet to map the terrain beneath.
“This is the first time we have seen a volcano beneath the ice sheet punch a hole through the ice sheet,” Vaughan said.
Heat from a volcano could still be melting ice and contributing to the thinning and speeding up of the thinning Pine Island Glacier, which passes nearby, but Vaughan doubted that it could be affecting other glaciers in West Antarctica, which have also thinned in recent years.
Volcanic heat “cannot explain the more widespread thinning of West Antarctic glaciers that together are contributing nearly 0.2mm per year to sea-level rise,” Vaughan added, “This wider change most probably has its origin in warming ocean waters.”