Fault Tectonics of the East Texas Basin

Principal fault systems in the East Texas Basin were examined in terms of their distribution, geometry, displacement history, and possible origins. All the faults studied are normal and moved syndepositionally over approximately 120 Ma (million years); some have listric shapes and associated rollover anticlines. The faults formed by processes associated with gravitationally induced creep of the Louann Salt, such as gliding over a salt decollement zone, crestal extension and collapse over salt pillows and turtle structures, and salt withdrawal from beneath downthrown blocks. None of the fault zones were caused by marginal flexure of the basins or salt diapirism; there is little evidence of basement control. Paucity of data prevents a reliable interpretation of the Mount Enterprise Fault, but our data suggest that none of the fault zones in this basin pose a seismic threat to a hypothetical nuclear-waste repository in the Gulf Coast area.