A suggested hypothesis is that the basement under the eastern United States consisted of many "miniplates," and that movements of these "miniplates" were responsible for many of the structures in the Gulf Coast basin. Geologists working in the eastern United States have found evidence of continual compressive forces from the southeast during much of the Paleozoic Era. Compression was replaced by tension after the Allegheny orogeny.

The Gulf Coast basin miniplate lies between the Texas megashear, or a closely related fault, and another megashear which extends from under the eastern Gulf of Mexico to the east end of the Ouachita Mountains near Little Rock. A stable miniplate, of which the Llano uplift is a part, acted as a buttress against the northwest movement of the Gulf basin plate.

The Gulf basin plate is believed to have moved more than 400 mi during the pre-Mesozoic compressional cycle. Rebound followed the cessation of compressional forces and a Mesozoic basin was formed over most of the Gulf basin plate. Many of the structures in the post-Paleozoic sediments resulted from rebound associated tension acting on zones of strength and weakness in pre-Mesozoic rocks.

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