The Cretaceous-Paleogene Mexican orogen: Structure, basin development, magmatism and tectonics

Although potential tectonic mechanisms for shortening in the Mexican orogen remain debated, our analysis indicates that orogenic wedge development took place in a retroarc setting that postdated consolidation of the hinterland oceanic assemblages, which lay offshore western Mexico during Albian time. Orogen development followed a protracted period of early Mesozoic extension that affected most of the Mexico due to the combined effects of Laurentia-Gondwana separation and long-term Triassic-Jurassic rollback of a paleo-Farallon plate. Slab rollback ultimately resulted in the development of a marginal basin, the Arperos basin, between a rifted Late Jurassic magmatic arc and mainland Mexico. Initial shortening in the Mexican orogen, which followed Arperos basin closure and Guerrero superterrane accretion by ~ 5-10 Ma, was coeval with voluminous magmatism on the Pacific margin of Mexico, drowning of the western carbonate platforms and onset of foreland-basin sedimentation in Cenomanian time. Subduction of the Farallon slab from early Late Cretaceous to Eocene time was thus the primary driving mechanism of shortening in the Mexican orogen.