The origin of the Gulf of Mexico basin and its petroleum subbasins in Mexico, based on red bed and salt palynostratigraphy

The most important red-bed and salt sequences in Mexico are Jurassic and are located in eastern Mexico in or around the Gulf of Mexico. Most of these rocks are Middle Jurassic, and they are overlain almost always by evaporitic sequences that mark the beginning of the Middle Jurassic transgressive sequence. In some places, they overlie pre-Jurassic rocks. Mesozoic red-bed sequences have recently been dated with organic and inorganic components of palynological residues. Information from red-bed sequences in the Los San Pedros Allogroup and Huayacocotla Group (Rhaetic-Liassic age in the Huayacocotla-El Alamar Basin), La Joya Formation (Middle Jurassic age in the Sabinas Subbasin), Rosario and Cahuasas Formations (Middle Jurassic age in the Tampico-Misantla Subbasin), and Todos Santos Formation (Middle Jurassic age in the Veracruz and Tabasco-Chiapas-Campeche Subbasins) allows us to construct a model for the origin and evolution of the Gulf of Mexico. The model includes three different stages: (1) the formation of one (or two?) Rhaetic-Early Liassic wrench or shear basin(s) (Huayacocotla-El Alamar Basin) related to the evolution of the Pacific convergent system; (2) formation of the Tampico-Misantla Subbasin during the late Liassic as a result of the southwest displacement of the Huayacocotla and Tlaxiaco Blocks along the Tampico-Lázaro Cárdenas and Teziutlán-Acapulco Megashears; and (3), the origin during the Middle Jurassic of the Gulf of Mexico Basin and the Sabinas, Veracruz, and Tabasco-Chiapas-Campeche Mexican petroleum subbasins as a result of the development of a triple junction. This triple junction allowed the northwestward displacement of the Texas-Louisiana block and the western region of Mexico from the stable Chiapas-Tabasco-Campeche-Yucatán block along the Lewis Clark-Bahamas and Texas-Boquillas-Sabinas lineaments and the Pico de Orizaba-Laguna Inferior Megashear.