Reprocessed 2-D seismic data across the Wilcox Depotrough show that it is located between partially extended upper slope strata and a completely detached raft block, which extends from Starr County northward to Live Oak County, Texas. Seismic data show little evidence of significant salt evacuation and/or extrusion. Forward modeling suggests that extensional rafting with ramp-flat fault trajectories on several detachment levels can provide all the accommodation. The raft system may be segmented along strike by switching vergence of the master fault cutting the Cretaceous, thereby providing possible local escape points for Wilcox sediments to more distal locations.

Extensional rafting is known and incorporated into exploration strategies along the South Atlantic margins of West Africa and Brazil, but not in South Texas. Back-filled incisions across raft structures, turbidites draped over or between rafts, and basin floor fans downdip of rafts are known exploration targets elsewhere but not recognized in South Texas. Additionally, because updip extension requires downdip contraction, contractional structures of this age could exist basinward of the raft. Employing a raft model explains why Upper Wilcox shelf margin deposition was confined and opens new exploration possibilities in this mature producing trend.