At the site of the dinosaur-killing crater, scientists find a surprise

When colossal asteroids rock Earth, it's not all doom and gloom.

The menacing asteroid that wiped out non-avian dinosaurs left a colossal marine crater in what's now the Yucatan Peninsula. But after analyzing deeply drilled rock core from the impact site created by the six-mile-wide asteroid, geologists have found compelling evidence that life soon thrived in the basin following the seismic episode.

The asteroid's impact stoked nutrients and chemicals to be released from beneath the seafloor, a process called hydrothermal activity. Similar activity naturally occurs today in the deep sea, where hydrothermal vents emit superheated chemical-rich fluid into the water, feeding unique colonies of life, including huge tubeworms, crabs, fish, microorganisms, and beyond.

"This study reveals that impact cratering events, while primarily destructive, can in some cases also lead to significant hydrothermal activity,” Steven Goderis, a researcher at Vrije Universiteit Brussel in Belgium who co-authored the study, said in a statement. “In the case of Chicxulub, this process played a vital role in the rapid recovery of marine ecosystems.”

The research was published this week in the peer-reviewed journal Nature Communications.

The colossal impact event, which triggered a mass extinction event over much of Earth's land and ocean environments, also filled the present-day Gulf of Mexico with nutrients for at least 700,000 years, the researchers concluded.

In the core drilled from the impact site, called "Chicxulub crater" (which you should Google for a novel Google-created search result), researchers found a ratio of the metallic element osmium that is associated with asteroid remnants. When the asteroid struck this region, its pulverized particles — which contained osmium — mixed beneath the seafloor and were emitted into the water, before eventually settling back down on the seafloor. When scientists drilled into the ocean bottom, they brought up this ancient seafloor, revealing that hydrothermal fluid containing asteroid remnants flowed into the gulf for hundreds of thousands of years.

The impact, which precipitated widespread hydrothermal activity, ultimately created a nutrient-rich oceanic bath, the researchers say.

A graphic showing how the environment in the Chicxulub crater following the impact could have spawned rich hydrothermal activity in the enclosed Gulf of Mexico. Credit: Sato et al.

A gravity anomaly map of the Chicxulub crater in the Yucatan Peninsula. Credit: NASA Shuttle Radar Topography Mission

"After the asteroid impact, the Gulf of Mexico records an ecological recovery process that is quite different from that of the global ocean, as continuous hydrothermal activity has created a unique marine environment," Honami Sato, an earth scientist at Japan's Kyushu University who led the research, explained.

If such a cataclysmic event could create extremely habitable conditions on a region of Earth, the same might happen on other worlds, too. It could happen on ocean moons, or in a related way, perhaps even on desert worlds. Mars, for example, is a planet bombarded with meteor strikes. Such impacts could melt the plentiful water ice in parts of Mars' subsurface, creating an inviting environment for microbes to thrive.

The risks of an asteroid impact

Fortunately for us earthling land-dwellers, the odds of a cataclysmic space rock impact are exceedingly small. Here are today's general risks from asteroids or comets both tiny and very large. Importantly, even relatively small rocks can still be threatening, as the surprise 56-foot (17-meter) rock that exploded over Russia and blew out people's windows in 2013 proved.

• Every single day about 100 tons of dust and sand-sized particles fall through Earth's atmosphere and promptly burn up.

• Every year, on average, an "automobile-sized asteroid" plummets through our sky and explodes, according to NASA.

• Impacts by objects around 460 feet (140 meters wide) in diameter occur every 10,000 to 20,000 years.

• A "dinosaur-killing" impact from a rock perhaps a half-mile across or larger happens on 100-million-year timescales.