NW-SE Quaternary Extension and the emplacement of the Apan-Tezontepec Monogenetic Field, Northeast of Mexico Basin

The eastern portion of the Mexico basin, located within the Trans-Mexican Volcanic Belt (TMVB), is transected by right-stepping variably dipping NE-SW normal faults. The Apan-Tlaloc fault is a major discontinuity that divides the region into two contrasting areas with different structural and volcanic styles. a) The western area is characterized by horst-graben geometry with widespread Quaternary monogenetic volcanism and scattered outcrops of Miocene and Pliocene rocks. b) The eastern area is dominated by tilted horsts with a domino-like geometry with widespread Miocene and Pliocene rocks and scattered Quaternary monogenetic volcanism. Gravity data suggest that this structural geometry continues into the calcareous Mesozoic basement. Normal faulting was active since the Pliocene times with three stage of extension, with a high dilatational activity during the Pliocene late-Pleistocene, according with the age of the Apan-Tezontepec Volcanic Field. Statistics analysis of cone elongation, instability of volcanic cone , besides with kinematics analysis of faults show during the Pliocene late-Pleistocene was emplacement the ATVF under a stretching oriented NW-SE The activity in some portions of the Apan Tlaloc-fault system continues today as indicated by earthquake swarms recorded in 1992 and 1996 and deformed soil horizons.