The Relationship Between Inverted Normal Faults and Pure Thrusting During the Tectonic Inversion of the Domeyko Cordillera, Northern Chile: Structural and Seismic Interpretation and Analog Modeling Experiments

The orogenic growth of the Domeyko Cordillera was induced by a positive tectonic inversion. In this work, we have validated this interpretation from new field data, which were combined with 2-D reflection seismic profile interpretations obtained along the Central Andes forearc of northern Chile. To compare with this information, we performed a new series of Analog Models dealing with positive tectonic inversion. On the basis of this, we propose an integrated kinematic model that describes the relationships between extensional structures, inversion structures, and pure thrust faulting. The proposed model is developed with an initial syn-rift phase related to the filling of half-graben basins, followed by a positive tectonic inversion phase. Our models show two main structural styles: partially inverted normal faults and newly formed pure thrust faulting. The partial inversion of previous normal faults represents the initial stage of exhumation of the syn-rift deposits. The pure thrusting consists of east-verging faults, which decapitate early or partially inverted normal faults. The first type of structures are compared with west-verging inverted, or partially inverted, normal faults, inversion anticlines, and buttressing structures, exposed on the western flank of the Domeyko Cordillera. The second type of structures are compared with the east-verging thrust faults exposed on the eastern flank of the Domeyko Cordillera. Finally, we consider that the architecture of the Domeyko Fault System is associated with inversion structures and pure thrust faulting; being these faults first-order structures that led to the orogenic growth of the Domeyko Cordillera from the Upper Cretaceous.