Faulting in the northeast part of the Mississippi salt basin is principally local graben-type resulting from salt doming. On deep-seated salt-dome structures, the faulting has common characteristics throughout the area which can be applied to great advantage in subsurface interpretations.

Faults are localized over each dome. The general fault strike is usually parallel with the long axis of the deepseated dome with which it is associated. Faulting over deep-seated salt domes can usually be related to derivative gravity minimums which are expressions of the salt uplifts causing the faulting. Generally, the relative intensity of the derivative gravity minimum becomes greater as the complexity of the faulting becomes greater.

Fault dips over deep-seated domes in the northeast part of the Mississippi salt basin average approximately 45° in the Upper Cretaceous and 60° in the Lower Cretaceous.

The increase in throw with depth is principally a result of lengthening of stratigraphic section in the downthrown block relative to the same section in the upthrown block. This lengthening of section is caused by thickening of the downthrown beds, and by preserved wedges below unconformities in the downthrown block which are absent in the upthrown block.

The crests of structures at Lower Cretaceous horizons through this area are commonly located near one side of a graben system. The faults on this side, termed "axial faults," generally bisect the anticlinal crest so that closure is present on both their upthrown and downthrown sides. Lower Cretaceous production is most commonly found along the structural crest on both sides of the axial faults.

Faults with opposing dip on the opposite side of the graben, termed "flank faults," are farther removed from the structural crest and exhibit closure only on the upthrown side. Flank faults provide potential traps if upthrown reservoir beds remain against impervious strata in the downthrown segment during growth of the fault.

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