The Gulf Coast of Texas and Louisiana has been geophysically explored more intensively than any comparably large area in the world, but the indications of the depth and configuration of the basin derivable from this work are limited. Gravity data are of very little use. Magnetic data give general indications of the basement depth. Normal reflection-seismograph data give detail between and beyond bore holes but rarely reach to greater depths than the deepest drilling. Special reflection surveys over a few salt domes give indications of the depth to the base of the salt column.
The principal conclusions reached by consideration of all the available geophysical results are: (1) The regional dip toward the Gulf of Mexico extends to the coast line without any indications of a synclinal axis at or immediately beyond the coast, and (2) The thickness of sediments at the coast line is about 40,000 feet, and (3) Pre-salt sediments are thin, absent, or metamorphosed.