Abstract

The western Gulf of Mexico is a passive margin where Tertiary gravity spreading processes resulted in a regional extensional-contractional linked system. The extension associated with growth faulting on the coastal plain and continental shelf is accommodated downdip by compression on a Paleogene detachment. As a result, the contractional growth structures of the Mexican Ridges evolve during the Neogene covering the western slope of the basin in front of Tamaulipas and Veracruz states, Mexico.

The Mexican Ridges Fold Belt is characterized by symmetric and asymmetric detachment folds and break-thrust detachment folds. Most of the contractional folds are multi-detachment structures. The basal detachment consists of overpressured shales of the upper Eocene. An additional detachment has been identified in the Oligocene.

We use a regional tectonic-structural map and depth-converted cross-sections from the north and south province to: 1) illustrate differences in trends and geometry of growth structures, 2) determine age and phases of deformation interpreting pre- and syn-tectonic strata, and 3) propose tectonic evolution models of the north and south Mexican Ridges.

This structural analysis is useful to characterize not only structural styles but potential hydrocarbon traps, especially in the north Mexican Ridges. In this area the extensional-contractional linked system interact with salt and shale tectonics. In addition, we have noted that this interaction correlates with highly active petroleum systems. This includes migration and trapping of hydrocarbons resulting in seismic anomalies, overpressured structures, gas chimneys, and sea floor hydrocarbon seeps that require more detailed evaluation.