The Chicxulub asteroid impact that ended the dinosaur era left the site in what is now Mexico hot enough to sustain underground microbial life for at least 8 million years. New analysis of rock cores shows the hydrothermal system lasted far longer than earlier estimates suggested.
The 15-kilometre-wide asteroid struck 66 million years ago and melted about 10,000 cubic kilometres of rock. Seawater combined with the molten material to form a porous hydrothermal system that extended several kilometres underground. Researchers led by Annemarie Pickersgill at the University of Glasgow drilled one kilometre into the crater and dated minerals using argon isotopes. The ages ranged from the time of impact to about 58 million years ago, indicating hydrothermal activity continued for 8 million years. Sulphur isotopes in the cores also point to microbial life that recovered quickly within the system. Chris Kirkland of Curtin University said the findings show large impacts can create long-lived underground habitats rather than simply destroying environments. The results suggest early Earth impact craters may have offered extended refuges for life, and similar systems could have existed on other planets.