The asteroid that struck Mexico's Yucatan Peninsula 66 million years ago, carving a crater nearly 200 kilometres across and ending the reign of the non-avian dinosaurs, left a far longer-lasting legacy underground than scientists had realised. New research shows that the hydrothermal system created beneath the crater by the impact persisted for at least eight million years, roughly four times longer than earlier estimates and the longest-lived impact-generated hydrothermal system yet documented.
The evidence comes from argon-argon dating of potassium-rich feldspar in samples recovered from the crater's peak ring during Expedition 364 in 2016. Dr Annemarie Pickersgill of the Scottish Universities Environmental Research Centre, who took part in the expedition, performed the dating, which yielded feldspar ages spanning roughly 66 to 58 million years ago. Updated computer simulations, co-developed with University of Glasgow colleagues, suggest high rock permeability, sustained impact heat and natural geothermal conditions kept the system alive.
The findings, published in Communications Earth and Environment, matter beyond the Chicxulub story. The impact, caused by an asteroid around 10 kilometres wide, wiped out roughly three-quarters of plant and animal species, yet long-lived hydrothermal systems of this kind are also considered candidate cradles for microbial life, on the early Earth and potentially on other worlds. Funders included ECORD, the International Continental Scientific Drilling Program, NERC and the Leverhulme Trust.