Tectono-stratigraphic evolution of eastern Mexico during the break-up of Pangea: A review

The Lower Jurassic–Cenomanian successions of Mexico can be grouped into two different tectono-stratigraphic systems that were developed under the influence of two distinct geodynamic processes: 1) the Mesozoic Atlantic System of Mexico, which occupies the eastern two thirds of the country and was dominantly influenced by the break-up of Pangea and consequent opening of the Atlantic Ocean, and 2) the Mesozoic Pacific System of Mexico, which is exposed along its western margin and was controlled by the subduction of the Farallon plate beneath the Pacific margin of North America. The Mesozoic Atlantic System of Mexico can be subdivided into two tectono-stratigraphic subsystems representing the two main tectonic stages of the break-up of Pangea. The Early–Middle Jurassic rift subsystem was developed during the initial stage of lithospheric attenuation of western equatorial Pangea, which is evidenced by the opening of a number of right-lateral transtensional troughs that were opened according to the NW-SE regional extension imposed by North America-South America divergence. Rift-related troughs were progressively infilled by continental to marginal-marine deposits and, locally, by volcanic lava flows that display a geochemical signature typical of supra-subduction settings. Based on these characteristics, the rift subsystem is interpreted in this work as a hybrid tectono-stratigraphic domain that displays characteristics that are typical both of the Mesozoic Atlantic System of Mexico and Mesozoic Pacific System of Mexico, reflecting the superposition of the Atlantic and Pacific tectonic processes during the initial phase of North America-South America divergence. By late Callovian time, most of intra-continental extension in western equatorial Pangea had occurred and was followed by anticlockwise rotation of the Yucatán block to its present position and initial seafloor spreading in the Gulf of Mexico. The opening of the Gulf of Mexico promoted the incursion of marine waters in eastern Mexico and the onset of carbonate basins and platforms that make up the Late Jurassic–Cenomanian drift-and-cooling subsystem. The lack of arc-like igneous rocks in the drift-and-cooling subsystem suggests that by the late Callovian the Mesozoic Atlantic System of Mexico was developed independently of the tectonic processes related to subduction along the Pacific margin.According to our synthesis, the Mesozoic Atlantic System of Mexico represents a unique stratigraphic record that was developed, at least in part, under the combined influence of two main tectonic processes that are: 1) the divergence between North America and South America and 2) the subduction of the Farallon plate. In light of this, the Mesozoic Atlantic System of Mexico can be considered a natural laboratory to explore the evolution of complex geodynamic settings related to the interaction of plate tectonic boundaries.