Volcanic and tectonic evolution of central Mexico: Oligocene to present

Based on a synthesis of geochronologic, stratigraphic, and structural data of the volcanic terrains of central Mexico the spatial and temporal relations between the Sierra Madre Occidentale (SMO) and the Mexican Volcanic Belt (MVB) are reconstructed. An analysis of 520 radiometric ages integrated with the available geological data shows that the migration of volcanism from the NNW trending, dominantly silicic SMO arc to the roughly E-W trending intermediate to mafic MVB arc occurred gradually in response to the progressive development of the Acapulco trench in early to middle Miocene times. The tectonic evolution of the western and central parts of the MVB is characterized by a middle Miocene phase of transcurrent faulting followed by a transtensional to extensional phase between the late Miocene to the present. The coincidence between the onset of the MVB and the middle Miocene phase of transcurrent faulting leads us to propose that the NW-SE and E-W transcurrent faults could have provided preferential crustal magma paths, allowing the formation of the MVB with its oblique orientation with respect to the trench. -from Authors