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Late Cretaceous-Tertiary Shortening and Uplift History in Southern Mexico, and Implications for Sedimentation in Southern Gulf of Mexico: Part 2, Restored Sections


New restored sections across the Sierra de Juarez, Veracruz Basin and adjacent offshore Gulf of Campeche are presented. Attempts are made to estimate the structural timing, the shortening, the displacement, the uplift and volume of eroded material, and the original Cretaceous extensional geometry. We suggest that the detachment surface on which the Zapotitlán-Chivillas back arc basin opened was re-played as a major cataclastic thrust zone emplacing arc-modified crystalline basement over a Laramide thrust stack dominated by carbonates, but also containing siliciclastic units. The steeply dipping Oaxaca fault zone is interpreted as an oblique extensional fault zone thrown across these pre-existing thrust structures, but which may be located over an older basement structure. The enveloping surface of the frontal Laramide folds of the Sierra de Juarez and floor of the associated Palaeogene foreland basin now dip towards the Gulf of Mexico, not, as one might expect, back into the mountain belt. They are re-oriented by a major crustal flexure at the Jurassic-Lower Cretaceous transform margin, a structure which may have developed in relation to a change in the dip of the underlying subduction zone, as described in the companion talk to this one.