A ring of sinkholes in Yucatán traces the asteroid that ended the dinosaurs
Across the flat limestone of Mexico's Yucatán Peninsula, a semicircle of cenotes marks a shock wave from the Chicxulub impact 66 million years ago. The land above that buried crater later cradled Maya cities, and even the peninsula's name may come from locals telling Spaniards they did not understand.
Covering roughly 181,000 square kilometres of southeast Mexico plus parts of Belize and Guatemala, the peninsula juts northeast between the Gulf of Mexico and the Caribbean, with the Yucatán Channel separating it from Cuba. It rests on the Maya Block at the southern tip of the North American plate. Because some geographers draw the Central America line at the Isthmus of Tehuantepec, the peninsula can be placed in either region, though politically Mexico counts as North America.
Everything here is carbonate rock, mostly limestone with some dolomite and evaporites, forming a flat karst plain with no surface confinement. Collapsed sinkholes called cenotes pepper the northern lowlands. A space rock perhaps 10 to 15 km wide struck near the town of Chicxulub at the end of the Cretaceous, and the Alvarez hypothesis ties that blow to the dinosaur extinction. Support includes the semicircular Ring of Cenotes, shocked quartz and glassy tektites. The climate grades from semi-arid in the northwest, under 800 mm of rain a year, to about 2,000 mm in the southern Petén Basin, and the low terrain leaves it exposed to hurricanes such as Gilbert, Wilma and Dean.
Human presence runs deep. In 2020 divers led by Jerónimo Avilés recovered from Chan Hol cave near Tulum the skeleton of a woman about 30 who died at least 9,900 years ago, her skull fractured and marked by a syphilis-like infection. Researcher Samuel Rennie argued such finds point to at least two physically distinct populations in Mexico as the Ice Age ended.
The peninsula formed the heart of the Maya lowlands, home to Chichen Itza, Coba, Tulum and Uxmal. After a 9th-century collapse to the south, power shifted north, and Maya kingdoms held off Spanish conquest for close to two centuries. The Caste War from the 1840s expelled non-natives, and the Maya state of Chan Santa Cruz survived until the Mexican army took it in 1901. As for the name, one story popularised by Hernán Cortés says Maya speakers answered Córdoba's 1517 questions with a phrase meaning I don't understand; another links it to the yuca plant.
Source: Yucatán Peninsula
