Paleogeografía de México del Paleozoico al Cuaternario y su relación a la tectónica

Abstract

The geologic events which occurred in Mexico from Paleozoic to Recent times are surveyed. It is shown that the course of historic geology and its physiographic expression in paleogeography have been determined by various orogenies, including the Appalachian, the Palisades eruptive episode, the Nevadan and finally, the Laramide orogeny. Paleogeography of the Lower and Middle Paleozoic shows that apparently there was no connection between the seas of the Tiaxiaco sub-basin and the seas covering the N arid NW regions of the country. The same is true for the Upper Paleozoic, in particular the Permian, which features basins in Northern and Central Mexico and platforms in Sonora and part of Chiapas. The major geologic perturbations produced large basins, or subsiding blocks covered by shallow seas, or flysch and redbed fills particulary in the Upper Triassic (Huizachal Formation) or the Middle Jurassic (Cahuasas Formation). These are found mostly in the Eastern and Northeastern part of Mexico. During Middle to Upper Mesozoic (Jurassic-Cretaceous) the transgressions were much more important than in earlier geologic periods. Towards the end of the era we find positive regions in Northern Baja California, Sierra Madre Occidental, Sierra Madre del Sur, and Chiapas. The Lower Tertiary marks the emergence of the Southern Continent of North America and the sea with draws gradually to its present boundaries in Quaternary (Pleistocene-Recent) times. The systems of folding resulted from great vertical and horizontal stresses as weel as gravitational effects. The general trend of these systems may be seem in the tectonic map.