ABSTRACT

The Gulf Coast and Mid-Continent areas of the southern U.S., in the past 500 million years, are postulated to have been the scene, first, of continental approach and collision, and later of a rifting almost at the site of the suture. Spreading apart of the newly formed continents proceeded to the present. This paper presents a review of these events. A series of cross sections and maps shows an interpretation of the tectonic evolution of the region beginning in Cambrian time and extending through the Neogene.

As extensions of the open ocean, epicontinental seas of Late Cambrian through Mississippian time deposited largely carbonate rocks over a vast region in what is now the Mid-Continent area. From Pennsylvanian time to the end of the Paleozoic, as the continents closed rapidly causing great instability in the area, terrigenous deposits dominated Mid-Continent sedimentation.

Collision of the continents occurred in about early Mid-Pennsylvanian time creating the Ouachita suture belt which contains the basinal rocks of the Early and Middle Paleozoic. By Triassic time the sea had withdrawn completely from the Mid-Continent area and rifting had begun south of the Ouachitas.

Plate tectonic movements have affected the distribution of hydrocarbon deposits in the Mid-Continent and Gulf Coast areas. The location and shifting through time of a sedimentational and tectonic hingeline may have been controlled in part by plate movement. Structure and trap style, timing in trap development, and quality of trap also may have been affected by plate tectonic movement, particularly in the late stages of continental approach (for the Mid-Continent) and the early stages of moving apart (for the Gulf Coast).