Cenozoic structural deformation between the southern Lamprea fold-belt and Salina del Bravo salt province by interacting salt and shale detachments, western Gulf of Mexico

Abstract

The Lamprea fold-belt is a 300 km-long, 20-60 km-wide, deep-water, passive margin fold-belt located southeast of the Salina del Bravo salt province and trending parallel to the eastern continental margin of Mexico. The Lamprea fold-belt detaches along Eocene shale layers to form a compressional toe of the gravitationally-driven system that forms a transitional domain between the salt province to the north and the shale-detached Mexican Ridges fold-belt to the south. Area-depth strain measurements performed for ten characteristic folds across two regional seismic profiles through the Lamprea fold-belt provide insight into its timing of deformation, depth to detachment, and controls on the pre-growth and syn-growth sedimentary deposits. Miocene-age deformation across the Lamprea fold-belt coincides with a phase of renewed salt canopy emplacement driven by ongoing up-dip sediment loading and extensional deformation west of the Salina del Bravo salt province. These results are consistent with early Miocene fold growth onset controlled primarily by the advancing salt canopy and only minor influence from underlying autochthonous salt. The timing of trap formation, tectonic interaction of salt bodies with shale structures, and the mechanisms for fold-belt formation all control hydrocarbon migration from deep Mesozoic source intervals into overlying Oligocene fold-belt reservoirs.