The oil possibilities of West Tennessee, Central Tennessee, Cumberland Plateau, and the Valley-and-Ridge Province are described in this summary.
West Tennessee.—West Tennessee is that part of the state west of the Western Valley of the Tennessee River and in the Mississippi Embayment section of the Gulf Coastal Plain. From the standpoint of oil potentialities two stratigraphic divisions are considered: (1) the overlying Cretaceous and Eocene beds, and (2) the underlying Paleozoic strata.
The Cretaceous and Eocene rocks consist of unconsolidated marine and nonmarine sands, marls, clays, lignite, and gravel. These rocks form an asymmetrical wedge, thickening westward from a feather edge on the east along the Tennessee River to about 1,000 feet in the northwestern corner of the state and about 3,000 feet in the southwestern corner. The beds dip westward about 25 feet per mile. In this wedge adequate source beds and reservoir rocks are probably present. It is doubtful, however, if many closed structures occur in the Cretaceous and Eocene strata as they exhibit little evidence of structure other than the homoclinal dip toward the west. Production would be more likely from stratigraphic traps, that is, lenses of sand tapering out updip toward the east into impervious clay. Location of such bodies would be difficult unless some type of geophysical exploration could detect their presence. Recent drilling in these beds has furnished no encouragement, one factor being the occurrence of fresh water in the sand.
The Paleozoic rocks underlying the Cretaceous and Eocene rocks in the Mississippi Embayment