Laramide Sedimentation and Deformation along Papalutla Fault System

The Papalutla fault system is a major northeast trending structure that bisects southern Mexico between Acapulco, Gro. and Jalapa, Veracruz. It is a long live structure and it is the boundary of Southern Mexico Paleozoic metamorphic basement (Acatlan Complex) and the Cretaceous Guerrero-Morelos calcareous platform (GMCP). Stratigraphic evidence suggests that the Papalutla fault controlled the Cretaceous sedimentation and deformation of GMCP during several episodes. Its northeast sector is hidden underneath the Transmexican Volcanic Belt; and further north it is the limit of the Cenozoic Veracruz Basin.

The Papalutla fault is segmented, with kinematics congruent with left strike slip; its thrust segment near Papalutla town is the most known feature which corresponds with a right bend in a left strike slip fault. Major Laramide thrust faults in southern Mexico show an array roughly orthogonal to the Papalutla system; they are the Oaxaca fault belt, Vistahermosa fault and the buried Gulf of Mexico's tectonic front. While these faults accommodated southwest – northeast shortening during Laramide deformation, Papalutla fault system acted as a major tear fault. It originated folding of GMCP rocks, and formed several tectonic basins as the Tehuitzingo-Tepexi basin. During Laramide deformation, the Papalutla fault system generated late Cretaceous clastic marine sedimentation at GMCP and Valsequillo region forming the Mexcala Formation. This is suggested by the sandstone provenance of the Mexcala Formation, since it contains clasts of metamorphic rocks derived from the Acatlán Complex. Evidence of previous tectonic activity of the Papalutla fault is the difference in thickness of Early to mid Cretaceous calcareous deposits at the GMCP compared to that on the Acatlan Complex, and the presence of metamorphic clast on Lower Cretaceous volcanic-clastic rocks of Zicapa Formation at the GMCP.