Nature

Etna, Europe's largest volcano IN 2001

The environmental catastrophe was caused by a (previously unknown) giant volcanic eruption in what is now south-west China. It unleashed a stream of lava wiping out marine life around the world.

The scientists can pin-point the eruption, despite the mind-boggling timescale, because it occurred in a shallow sea. This means that the record of the lava survives as a distinctive layer sandwiched between other layers of sedimentary rock containing datable marine fossils.

Paul with basalt lava flow behind him

The effects were calamitous because the volcano was near a shallow sea and fast-flowing lava mixing with water caused a violent explosion throwing huge quantities of poisonous sulphur dioxide into the stratosphere, cooling the planet and causing 'acid rain' downpours.

"... it's like throwing water into a chip pan - there's spectacular explosion producing gigantic clouds of steam," explains Professor Paul Wignall, a palaeontologist at the University of Leeds.

"The abrupt extinction of marine life we can clearly see in the fossil record firmly links giant volcanic eruptions with global environmental catastrophe..."

Investigating lava flow in Yunnan, China

Paul Wignall is a professor of palaeontology in the School of Earth and Environment, University of Leeds. It is has more than 90 academic staff, over 60 research staff and 140 postgraduate researchers.

The University of Leeds was rated the UK's eighth biggest research institution in 2008.