An oval basin named for the Mexica holds vast oil shelves
The Gulf of Mexico is an Atlantic marginal sea cupped by the U.S. Gulf Coast, Mexican states from Tamaulipas to Quintana Roo, and Cuba. The oval basin spans about 1.6 million square kilometres—nearly half shallow shelf—and holds roughly 2.4 million cubic kilometres of water.
Roughly 1,500 kilometres across, the basin links to the open Atlantic only through the Straits of Florida and to the Caribbean through the Yucatán Channel, so its tides stay tiny. Its floor is 41 percent slope, 32 percent shelf and 24 percent abyssal plain, dropping to 12,467 feet in the Sigsbee Deep. Its moisture drives weather far inland, including Tornado Alley storms, and offshore wells supply about 14 percent of American crude.
Before the late Triassic this spot was dry land deep inside Pangaea. Rifting opened valleys filled with red beds, then thinned the crust to about half its usual 40 kilometres, letting seawater in first from the Pacific across central Mexico and later from the Atlantic. Thick Louann Salt settled over the sinking floor; under the weight of later sediment, that salt now creeps upward into domes, and where seawater touches it, dense brine pools form on the seabed, from a metre wide to 20 kilometres long. Kilometres of mud eventually pushed the crust 10 to 20 kilometres below sea level.
The name echoes the Mexica, the Nahuatl-speaking Aztecs, who called the water the house of Chalchiuhtlicue, their sea goddess, while the Maya probably knew it as nahá, great water. Cortés wrote of a Sea of the North, and other charts tried Gulf of Florida, Gulf of St. Michael and Cathayan Sea. The label Gulf of Mexico reached a world map in 1550 and a written history in 1552, and French Jesuits used it by 1672.
In January 2025 an executive order from Donald Trump told federal agencies to call the American portion the Gulf of America, drawing objections from Mexican president Claudia Sheinbaum; a Marquette poll that February found 71 percent of respondents opposed. Around the shores live 15.8 million people in the U.S. region, 19.1 million in six Mexican states and about 3.2 million in western Cuba. By 1975 some 400 rigs housed over 10,000 offshore workers on a typical day. Rice’s whale, confirmed as its own species by 2021, lives only in the northern gulf.
Source: Gulf of Mexico
