Chicxulub Asteroid Impact Site: The Millions of Years of Heat That Wiped Out the Dinosaurs

The catastrophic Chicxulub asteroid impact, which occurred 66 million years ago, released immense energy and took at least 8 million years for the impact site to stabilize, fostering a warm underground ecosystem thriving with microbes.

Hitting what is now Mexico, the Chicxulub asteroid measured approximately 15 kilometers in diameter and triggered significant climatic shifts, resulting in the extinction of about 75% of Earth’s species. All non-avian dinosaurs faced extinction as a nuclear winter enveloped the planet for a minimum of 15 years.

Even the depths of the Earth felt the aftermath. “The Chicxulub impact caused deformation detectable up to 35 kilometers below the Earth’s surface,” explains Annemaire Pickersgill from the University of Glasgow.

This impact melted approximately 10,000 cubic kilometers of rock, and the interaction of molten rock with seawater resulted in hydrothermal systems rich in small pockets of heated water.

Research indicates the asteroid created a hydrothermal environment that extended several kilometers underground, as certain minerals only form in the presence of liquid water and heat. Surprisingly, the durations and extents of these hydrothermal systems appear to have been underestimated.

Previously thought to cool within 2 million years, Pickersgill’s research suggests the cooling process may have taken at least four times longer, providing more time for hydrothermal life to thrive.

“A major uncertainty regarding impact-generated hydrothermal systems like Chicxulub is how long the heat circulates water within the structure,” notes Pickersgill.

To investigate further, the research team drilled one kilometer into the crater, collecting rock cores. By analyzing the potassium decay into argon gas, they determined the age of the samples.

“Our findings showcase a range of ages from the impact event 66 million years ago to around 58 million years ago,” Pickersgill reports. “This implies hydrothermal activity persisted in at least some parts of the Chicxulub structure for 8 million years post-impact.”

Exploring sulfur isotopes in the rock cores indicates that microorganisms inhabited the hydrothermal system and exhibited rapid recovery following the cataclysm.

These findings imply that habitable hydrothermal conditions may have existed in early impact craters on young Earth and potentially on other celestial bodies for much longer than previously recognized.

“This opens up additional avenues for life to develop, evolve, and spread,” Pickersgill emphasizes. “The study bolsters the idea that early life could have established long-term habitats in impact craters, which may also extend to life on other planets characterized by large impact features.”

Chris Kirkland from Curtin University, Perth, Australia, adds that while there isn’t a definitive record of continued hydrothermal activity at Chicxulub, strong evidence suggests the site remained thermally active for millions of years.

“The significant impact doesn’t merely devastate the environment; it also creates long-lived underground systems that facilitate the circulation of hot fluids through fractured rock. These chemically rich environments could offer refuge to microorganisms and provide conducive conditions for the early steps toward life,” he concludes.