A large part of the Gulf Coast of the United States and the Gulf of Mexico is underlain at depth with deposits of bedded salt. In the Gulf Coast geosyncline the salt probably reaches a depth of 30,000–40,000 feet, as indicated by geophysical profiles. At such depths, the temperature of the connate salt is calculated to be about 450°–500° F. Because the plasticity of salt increases rapidly with rise in temperature, movement of salt upward through the overlying sediments would be greatly facilitated at the high connate temperature; and the formation of salt structures, such as domes and stocks, can be more easily explained.

In certain exploratory wells drilled in southwest Texas on or near salt structures, the temperatures within or adjacent to the salt are much higher than those that would be expected to be present according to the normal geothermal gradient. These abnormally high temperatures may be caused by the salt in these structures having retained much of its connate temperature as it moved upward toward the surface.