One of the most petroliferous structural features of the Gulf of Mexico basin is the Vicksburg fault zone of southern Texas and northeastern Mexico. For almost 300 mi the downthrown side of these down-to-basin faults is characterized by an alignment of oil and gas fields, representing a total ultimate reserve of more than 3 billion bbl of oil and 20 trillion ft³ of gas.

Although the Vicksburg fault-zone trend has been explored over a period of more than 30 years, it still is not clearly understood. The principal reasons for the lack of understanding are that the displacements are buried deeply and have been interpreted almost entirely from seismic records and well data.

The accumulation of the hydrocarbons associated with the fault zone is largely a result of two notable characteristics of the zone: (1) downbending of the downthrown block provided dip reversal necessary for the formation of anticlinal closures; and (2) faulting contemporaneous with deposition resulted in the formation of structural closure during deposition and, thus, in early entrapment of migrating oil and gas.

Throughout the zone the Vicksburg faults show a history of post-Eocene movement. However, data collected at widely separated places indicate the possibility of earlier movements. Maximum activity occurred during Oligocene and early Miocene time, when the terrigenous clastic sediments of the Vicksburg and lower Frio were being deposited. Faulting decreased and ceased during or shortly after deposition of the upper Frio.

In places, where the fault zone consists of multiple faults, movement shifted progressively from one fault to another.