ABSTRACT
Collapse faulting circumscribes salt-withdrawal basins in the salt-dome province of south Louisiana. Wherever a cluster of piercement salt domes or extraordinarily large salt masses are present, an associated basin is created when salt is withdrawn from the source bed to form the piercement salt features. Collapse of overlying sediments into the salt-withdrawal area accompanied by an adjoining rise of salt establishes a force couple between collapse and salt rise. The tensional, or torsional, stress is relieved by normal faulting downthrown toward the center of the salt-withdrawal area. Continued rising of salt masses around the periphery of the basin establishes a repetitive cycle of salt withdrawal, salt rise, force couple, and relief of stress by collapse faulting. The name collapse fault is applied to the faults circumscribing a salt-withdrawal basin.
The traps associated with collapse faults provide generally poor loci for the accumulation of oil and gas.
