The Chicxulub-Shiva extraterrestrial one-two killer punches to Earth 65 million years ago

• The K–T boundary (KTB) event is, in fact, a double event.
• The Chicxulub impact occurred first, and may be younger than the actual KTB.
• The Shiva impact occurred 40,000 years later, and is likely responsible for the KTB.

Two large asteroids struck Earth at almost the same time, 65 million years ago, causing the major extinctions recognized as ending the Mesozoic Era. Although occurring close together in time, the Earth's magnetic pole had moved from the South Pole to the North Pole in between, allowing a time difference between the impacts to be calculated. The first strike produced a ∼180 km diameter crater named Chicxulub on the Yucatan shelf of southern Mexico. The second hit the shelf of the northward drifting Indian continent in the southern Indian Ocean, producing a crater ∼450 × 600 km named Shiva. Hitherto, the main obstacle to verifying this scenario has been the paucity of geological sections containing evidence of both impacts. Here, we present such evidence, and conclude that the two impacts were separated by about 40,000 years.