RM-7 — Structure of the Permian Ochoan Rustler Formation, Southeast New Mexico and West Texas

W. L. Hiss, 1976, Scale 1:500,000.

The widespread occurrence, distinctive lithology, and relatively uniform thickness of the Rustler Formation of Late Permian Ochoan age over the Delaware basin, Northwestern shelf, and Central Basin platform make it an ideal marker bed that can be readily distinguished in drill cutting samples and on geophysical logs (Adams, 19 44} . The Rustler Formation is composed of a sequence of anhydrite and gypsum with interbedded dolomite and clay in the upper section and primarily clastics in the lower section. In places there is considerable salt in the section. The structural map contoured on top of the Rustler Formation was prepared using data obtained from a number of sources. Formation tops were taken directly from the Permian Basin Well Data System data file and geologic sections prepared by the Roswell and West Texas Geological Societies, from geophysical and lithological logs, and from maps prepared by Guyton and Associates (1958), Garza and Wesselman (1962), 1/hite (1971), Armstrong and McMillion (1961), Ogilbee , Wesselman, and Irelan (1962), and Runyan (1965).