Probing the hydrothermal system of the Chicxulub impact crater.

The similar to 180-km-diameter Chicxulub peak-ring crater and similar to 240-km multiring basin, produced by the impact that terminated the Cretaceous, is the largest remaining intact impact basin on Earth. International Ocean Discovery Program (IODP) and International Continental Scientific Drilling Program (ICDP) Expedition 364 drilled to a depth of 1335 m below the sea floor into the peak ring, providing a unique opportunity to study the thermal and chemical modification of Earth's crust caused by the impact. The recovered core shows the crater hosted a spatially extensive hydrothermal system that chemically and mineralogically modified similar to 1.4 x 10(5) km(3) of Earth's crust, a volume more than nine times that of the Yellowstone Caldera system. Initially, high temperatures of 300 degrees to 400 degrees C and an independent geomagnetic polarity clock indicate the hydrothermal system was long lived, in excess of 10(6) years.