High-Resolution Multibeam Reveals Surficial Character of the Perdido, Mexican Ridges, and Campeche Fold Belts; Deep Water Mexican Gulf of Mexico

Abstract

High-resolution multibeam data acquired in 100% of the Mexican Gulf of Mexico 750m and deeper as part of the TGS “Gigante” multi-client program (total area surveyed = 477,000 km2) provides unprecedented imaging of the surficial character of marine fold belts. Due to active structural processes and relatively low sediment accumulation rates, the structural styles of these fold belts are well exposed at the surface. With 100% coverage of the seafloor the lateral extent of structural domains can be readily defined. Deformation styles vary considerably across the Mexican Gulf of Mexico, from the Perdido fold belt in the northwest dominated by allochthonous salt and associated arcuate thin-skin folding through the Mexican Ridges characterized by more laterally continuous regularly spaced folds, to the highly variable Campeche salt-cored folds with diapir-related marine knolls. In addition to these general trends, the horizontal grid resolution of 15m reveals several regions of high angle faulting crossing folds or defining structural domain boundaries within each of the fold belts. Within the Mexican Ridges fold belt a zone of coupling across the décollement results in a buttressed deformation field comprising strike-slip faulting, deflected fold axes, and a collapsed circular graben. Structural highs provide the gravitational potential energy to drive a wide range of surficial processes. In the Perdido fold belt area there are large scale, slope-wide mass transport / debris flow systems that extend tens of kilometers down and along slope, covering hundreds of square kilometers of the seafloor (including one that narrows through a downslope gap before extending laterally downslope). In the Mexican Ridges area, many surficial features are very thin, low angle localized (not far traveled) landslides, including some with minimal internal deformation. In the Campeche area structural highs show localized collapse in apparent viscous flow. A set of structural domains delineated by seafloor morphology is presented as a basis to define areas of differing structural style. Examples of the structures characterizing each domain are presented.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017