The day the earth shook
Sixty-six million years ago, a 10-kilometer wide asteroid traveling up to 150,000 miles per hour struck the shallow sea covering what is now the Yucatán Peninsula. The impact created the 200-kilometer wide Chicxulub crater and released energy equivalent to more than a billion nuclear bombs. This event triggered a magnitude 11 earthquake, blasting 400 cubic miles of debris into the atmosphere and generating a mega-tsunami.
The Brazos River area, then a sea floor about 75 to 100 meters deep, was approximately 1,000 kilometers from the impact site. The initial waves from the impact may have been over 100 meters high, scouring the Gulf of Mexico. These waves and their powerful backwash ripped up the sea floor, mixing sand, mud, boulders, and marine life into a chaotic slurry. The resulting deposit, a sandstone complex several feet thick, sits within layers of fine mudstone that had accumulated quietly for millennia. This jumbled layer of rock, exposed by erosion along the Brazos River in Falls County, records of the hours and days following the impact that ended the Cretaceous Period.