Mexico Geography And Geology

Mexico’s Pacific Coast is part of the Ring of Fire, an area around the Pacific Ocean characterized by high tectonic and volcanic activity. Over the past millennia, eruptions and earthquakes have shaped Mexico’s jagged coastlines, broad mountain ranges, and enclosed valleys. Most spectacular are Las Barrancas del Cobre (Copper Canyon) in the state of Chihuahua, where multiple canyons converge to form a canyon four times the size of Arizona’s Grand Canyon.

The long and narrow strip of land known as the Baja Peninsula extends 1330km south from California, dividing the Sea of Cortés (Gulf of California) from the Pacific Ocean. Two lofty mountain ranges, the Sierra Madre Occidental to the west and the Sierra Madre Oriental to the east, cut a V-shape through the heart of the country. The region south of Mexico City at the base of this V, the Cordillera Neovolcánica, is the most volcanic in Mexico. Though many of the volcanoes have been dormant since the 1800s, Popocatépetl spewed ash over Puebla in 1994, and Colima’s Volcán de Fuego (Volcano of Fire) awoke in 2005. The eruption sent lava and ash 5km into the sky, causing evacuations in nearby villages.

Farther south are the Southern Highlands, a series of mountains, plateaus, and valleys in the states of Guerrero and Oaxaca. West of the Sierra Madre Occidental is a dry, flat region of mesas. Along the eastern coast of Mexico, a much wetter swampland runs from the Texas border to the Isthmus of Tehuantepec in the Yucatán Peninsula. Northeast of the Isthmus is the Tabasco Plain, and southeast are the Chiapas Highlands, an area of high mountains surrounding a large rift valley. Northeast of the Highlands, the flat Yucatán Peninsula extends into the Caribbean Sea, pockmarked with limestone caverns and cenotes, natural fresh-water caves. Cenotes once provided Mayan cities with water and served as ceremonial centers; today, divers plunge into their depths to admire the underwater gardens . Some scientists believe the unusually high occurrence of cenotes in the peninsula is related to the same meteor impact that may have killed the dinosaurs 65 million years ago. In the 1940s, an oil company drilling in the Yucatán uncovered evidence of what is now known as the Cráter de Chicxulub (a gigantic terrestrial bowl 180km wide and more than 200km deep. Buried half in land and half under the Gulf of Mexico, most scientists believe that this crater was the site of the meteor impact.