When it comes to magma, fluctuating temperatures don't mix.
That's what scientists at the University of Southampton are saying after identifying a possible cause for some of the world's largest volcanic explosions.
Researchers analyzed the eruption patterns of the Las Cañadas caldera in the Canary Islands -- an area that has generated at least eight major eruptions in the past 700,000 years.
By studying the rocks that formed following a lava flow, it was determined that blending older, cooler magma with younger, hotter magma could be the root cause of history's most explosive eruptions.
The rocks, or 'nodules', "are special because they were ripped from the magma chamber before becoming completely solid – they were mushy, like balls of coarse wet sand," said Dr. Rex Taylor, Senior Lecturer in Ocean and Earth Science at the University of Southampton, in a statement.
"Rims of crystals in the nodules grew from a very different magma, indicating a major mixing event occurred immediately before eruption. Stirring young hot magma into older, cooler magma appears to be a common event before these explosive eruptions."
The findings have been published in the latest issue of Scientific Reports.