Traces of a Hydrothermal System Revealed after the Chicxulub Impact

A three-dimensional cross-section of the hydrothermal system in the Chicxulub impact crater and its seafloor vents. Image credit: Victor O. Leshyk for the Lunar and Planetary Institute.

The Chicxulub impact produced a multi-ring basin 240 kilometers in diameter on the Yucatán peninsula roughly 66 million years ago, ushering in the end of the Cretaceous era. This impact event was catastrophic for life on Earth, but recent findings show that it also modified the Earth’s crust significantly in a geologic sense by creating an extensive hydrothermal system. An international research team supported by the International Ocean Discovery Program and International Continental Scientific Drilling Program drilled into the peak ring of the crater in 2016 and obtained cores reaching a depth of 1,335 meters. A study of these core samples published by David Kring of the Lunar and Planetary Institute and colleagues shows mineralogical evidence for significant hydrothermal alteration. In particular, the rocks in the drill core include the mineral garnet that must have formed during hot fluid alteration with temperatures as high as 300 to 400 degrees Celsius. The magnetic clocks in these minerals suggest that this hydrothermal system was active for approximately 150,000 years after the impact. The hydrothermal system discovered at the Chicxulub impact site provides a geologically young analog to the ancient basin-forming impacts that shaped the early Earth and potentially created habitable environments for life. This research highlights that extraterrestrial impacts played an important role in the evolution of our planet, sometimes changing the Earth’s lithosphere and biosphere significantly. READ MORE