Around 100 million years ago, the east coast of Australia suffered volcanic eruptions so strong that they spewed zircon crystals as far away as Western Australia, according to new research from Curtin University.
The study, run by Dr. Milo Barham of the Department of Applied Geology, used advanced geochemical fingerprinting of the crystals to determine that they were the product of volcanic air fall from as far as 2,300 kilometres away.
Their existence implies the existence of super-eruptions, which have magnitudes tens to hundreds of times greater than anything in documented human history.
“Such distal projection of a unique volcanic mineral population demonstrates that super-eruptions were occurring in eastern Australia approximately 106 million years ago, during the break-up of the supercontinent Gondwana,” Dr Barham said.
Zircon crystals under an electron microscope [Image: Curtin University]
“The arrangement of land masses and atmospheric circulation at the time indicates that the recorded eruptions occurred during the southern hemisphere winter, when strong winds from the east would have pushed volcanic ejecta towards the west.”
The super-eruptions were capable of spreading tera-tonnes of volcanic material over thousands of kilometres, while affecting global climate systems, says Dr Barham.
“These super explosions are well known from the relatively recent past and have even been implicated in the evolution of our species,” Dr Barham said.
“However, the incomplete nature of geological sequences means that recognising these earth-shattering volcanic events is difficult in deeper geological time, millions to billions of years ago.
“If an event of this magnitude were to happen today it would have devastating effects on our society and likely would drive massive crop failures, famine and war.”
The findings have been published in Geology.