Scientists at the University of Leeds and the Chinese University of Geosciences in Wuhan have concluded that a massive volcanic eruption in Sichuan province caused a mass extinction of life in the oceans around 260 million years ago. From Science Daily:
The eruption in the Emeishan [sic] province of south-west China unleashed around half a million cubic kilometres of lava, covering an area 5 times the size of Wales, and wiping out marine life around the world.
Unusually, scientists were able to pinpoint the exact timing of the eruption and directly link it to a mass extinction event in the study published in Science. This is because the eruptions occurred in a shallow sea – meaning that the 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 directly after the eruption shows mass extinction of different life forms, clearly linking the onset of the eruptions with a major environmental catastrophe.