The Berkeley researchers - who published their work online April 30 in the The Geological Society of America Bulletin - cited the "uncomfortably close" coincidence between the Deccan Traps eruptions and the asteroid impact 66 million years ago. Team leader Mark Richards of UC Berkeley said in a statement:
If you try to explain why the largest impact we know of in the last billion years happened within 100,000 years of these massive lava flows at Deccan ... the chances of that occurring at random are minuscule.Richards had proposed in 1989 that plumes of hot rock, called "plume heads," rise through Earth's mantle every 20-30 million years and generate huge lava flows, called flood basalts, like the Deccan Traps. It struck him as more than coincidence that the last four of the six known mass extinctions of life occurred at the same time as one of these massive eruptions.
Comment: See also: Forget About Global Warming: We're One Step From Extinction!