Chicxulub impact site took 8 million years to cool
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- Annemarie Pickersgill of the University of Glasgow and colleagues drilled 1 kilometre into the Chicxulub crater and used potassium-argon dating on rock cores to show hydrothermal activity persisted from 66 to about 58 million years ago
- The new estimate of at least 8 million years for the impact site to cool is four times longer than the previous 2-million-year figure, according to the study in Communications Earth & Environment
- The 15-kilometre-diameter asteroid melted about 10,000 cubic kilometres of rock, creating a porous underground system of hot-water pockets detectable to depths of several kilometres and causing deformation at least 35 kilometres beneath the surface
- Sulphur isotopes in the cores provide evidence that microbial life existed in the hydrothermal system and recovered rapidly after the mass-extinction impact
- Independent expert Chris Kirkland of Curtin University says large impacts can create long-lived underground systems with chemically rich fluids, though he notes the record of continuous hydrothermal activity at Chicxulub is "not entirely unambiguous"
- The researchers argue the result means the earliest impact craters on the young Earth — and possibly other worlds — may have hosted habitable hydrothermal systems far longer than previously recognised
Why it matters: The finding quadruples the estimated lifespan of impact-generated hydrothermal systems, directly reshaping how scientists evaluate early-Earth and extraterrestrial craters as potential long-term microbial habitats — a framework Pickersgill's team explicitly applies to other worlds dominated by large impact structures.
