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Karen A. Pate1, John Dunbar1
(1) Baylor University, Waco, TX

Abstract: Evolution of faulting styles around salt domes

Salt dome growth is accompanied by the development of complex fault networks in the surrounding sediments. In this study we classify fault patterns adjacent to five salt domes within a single large and well imaged 3D seismic data set. The goal is to relate faulting style to salt geometry and to document changes in faulting style in different stages of salt dome growth. Four of five salt domes have two distinct classes of faults. Radial faults, trending at right-angles to salt-sediment interfaces, tend to dominate in the shallow sediment cover between the surface and a two-way travel time of 2.5 seconds. Faulting adjacent to these four domes, below 3.75 seconds, is dominated by a second class of faults that curve tangential to the salt sediment interface. Dome five exhibits only radial faults. We explain these two faulting styles in terms of changes in the orientation of the intermediate principal stress relative to salt-sediment interface with depth and the degree to which the dome is attached to the underlying source layer. Below 3.75 seconds in detached domes the intermediate stress is apparently tangential to the salt sediment interface, resulting in tangential fault geometries. Sediments adjacent to the deeper regions of detached salt domes may undergo an early phase of radial faulting, followed by a second phase of tangential faulting after the dome detaches from the source layer.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana