Giant volcanic eruption linked to global extinction
Scientists have uncovered evidence of a previously unknown giant volcanic eruption which they claim led to global mass extinction 260 million years ago.
The new study suggests the eruption in the Emeishan province of south-west China unleashed around half a million cubic kilometres of lava, covering an area five times the size of Wales, and wiping out marine life around the world.
The authors claim they have been able to pinpoint the exact timing of the devastating eruption and directly link it to mass extinction across the planet.
They claim it is due to the fact the ancient eruption occurred in shallow sea, and therefore its lava appears today as a distinctive layer of igneous rock sandwiched between layers of sedimentary rock containing easily datable fossilised marine life.
The layer of fossilised rock which appeared directly after the eruption contains evidence of mass extinction of different life forms, the authors write, which they suggest claim clearly links the onset of the eruptions with a "major environmental catastrophe".
It's believed the collision of the lava with the shallow sea would have caused a violent explosion during which vast amounts of sulphur dioxide were thrown up into the stratosphere.
Commenting, Professor Paul Wignall, a palaeontologist at the University of Leeds, and the lead author of the paper, said: "When fast flowing, low viscosity magma meets shallow sea it's like throwing water into a chip pan there's spectacular explosion producing gigantic clouds of steam."
Scientists believe the presence of the sulphur dioxide in the atmosphere would have led to the planet cooling and ultimately resulting in an outburst of acid rain.
"The abrupt extinction of marine life we can clearly see in the fossil record firmly links giant volcanic eruptions with global environmental catastrophe, a correlation that has often been controversial," Professor Wignall concludes.
28 May 2009, 23:31