T. Rex and the Crater of Doom the Brazos river that a tsunami has swept across the Gulf of Mexico millions of years earlier. The discovery was made thanks to a graduate student named Alan Hildebrand that notified Alvarez of the evidence of a crater on the Yucatan peninsula, which had never been published in the scientific literature by the Mexican petroleum geologists that had found it. The age of the crater needed to be determined if it was going to be a candidate for the KT boundary impact, but access to the region was limited by the crater being buried over time and the core samples
Yucatán Peninsula years ago was caused by an asteroid impact somewhere in the greater Caribbean Basin. The deeply buried Chicxulub crater is centered off the north coast of the peninsula near the town of Chicxulub. The now-famous "Ring of Cenotes" (visible in NASA imagery) outlines one of the shock-waves from this impact event in the rock of ~66 million years of age, which lies more than 1 km below the modern ground surface near the centre, with the rock above the impact strata all being younger in age. The presence of the crater has been determined first on the surface from the