Interaction Between Counter Regional Faults, Lateral Salt Sheets and Sediment Fairways Offshore Louisiana

Brad Patton, James F. Fox

The offshore Louisiana salt basin is structurally dominated by complex salt features and their related fault systems. There is a dynamic but poorly understood relationship between counter regional faults and laterally emplaced salt sheets. These structural features control sedimentation patterns and have a direct affect on the depositional fairways that are being actively explored beneath salt.

Counter regional faults develop along relict salt walls which are formed due to regional extension. These salt walls serve as feeders for either vertically or laterally emplaced features. As the salt migrates, the salt feeder begins to thin, causing the overlying sediments to collapse into a fault dominated syncline. The accommodating syncline collects sediment, and differential loading causes the salt to mobilize further, providing an additional drive mechanism for lateral injection of the salt.

The timing on counter regional faults also appears to be of importance because they are related to relative sea level changes and times of major sediment switching. Counter regional faults form in long linear trends, indicating there could be a relationship between the formation of these faults and deep, presalt basin faults. All of these factors combined illustrate the dominant impact that these structural features have on sedimentation patterns in the Gulf of Mexico.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995