The tectonic origin of the Sierra Madre Oriental is related to three events that occurred during the lower part of the Paleogene: first, the opening of the North Atlantic, faster in its northern part relative to its southern portion; second, isostatic imbalance due to the absence of mass in the Gulf of Mexico caused by the displacement of the Yucatan block southwards along the Tamaulipas-Oaxaca transform belt and; third, the subduction of the Farallon Plate, on the pacific coast of Mexico. These three contemporaneous tectonic events explain the different structural styles of northeastern Mexico where "en èchelon" folds are observed in the Sabinas Basin and in the Tamaulipas Archipelago, whose deformation is only explainable under a state of simple shear stress; the folded and thrusted orogen of the Sierra Madre Oriental with general vergence to the northeast and a curved salient in the Monterrey area, only explainable by a gravitational slip due to the subsidence of the eastern part of Mexico, and by the gentle tilting of the pre-Mesozoic basement caused by the subduction of the Farallon Plate.
Geological Society of America Abstracts with Programs. Vol. 58, No. 3, 2026