In early 1937, a salt dome was defined by Gulf Oil in Lamar County, Mississippi, the first to be found in that state. Oil discoveries related to salt domes identified by gravity surveys proceeded at an average rate of one per week for more than twenty weeks, according to Eckhardt, so it can be said with justification that Gulf Oil discovered the Mississippi Salt Basin through gravity surveying.
The Mississippi Salt Basin is a regional gravity high, and the Wiggins Arch, south of the basin, is a regional gravity low. One explanation for this calls on crust-mantle effects, as illustrated here. The basin would be a “neck” of thinned crust associated with uplift of dense mantle, and the Wiggins Arch would be interpreted as a block of low-density crust left behind as the Gulf of Mexico opened when Yucat rotated away.