~66 million years agoReputable sourceDebated
The Deccan Traps Erupt
On the timeline · around ~66 million years ago · The Cretaceous
What happened
Around the end of the Cretaceous, one of the largest volcanic events in Earth's history — the Deccan Traps, in what is now India — poured out immense floods of lava over hundreds of thousands of years, releasing climate-altering gases across the boundary.
Why it matters
Scientists still debate whether this volcanism, the Chicxulub asteroid impact, or the two together drove the mass extinction — but the eruptions almost certainly stressed global ecosystems.
How we know
The Deccan eruptions spanned the extinction boundary. Researchers disagree on their exact role: some models make the asteroid the decisive killer, others give volcanism a leading part.