For 10 points, a sudden increase in volcanic eruptions or impact with an asteroid are the two currently competing theories that explain what event that happened about sixty-five million years ago?
One explanation for this event is supported by the Deccan Traps. Evidence from Hell Creek, Montana appears to support both prevalent hypotheses. The most widely-known explanation for this event was first hypothesized after the discovery of an unusually iridium-rich layer in the Earth's crust, and was further supported with the discovery of the Chicxulub ("CHICK-shu-loob") crater off the coast of the Yucatan Peninsula. For 10 points, a sudden increase in volcanic eruptions or impact with an asteroid are the two currently competing theories that explain what event that happened about sixty-five million years ago?
One explanation for this event is supported by the Deccan Traps.
{extinction} of the dinosaurs [or K-T {extinction}; or equivalents]