Several thrust-fault exposures in the test site region place upper Precambrian and lower Paleozoic rocks over middle and upper Paleozoic rocks, and appear to be remnants of a single major system. The deepest known structural level of the system is buried west of Yucca Flat and is penetrated by a drill hole in which Precambrian and Cambrian clastics overlie middle and upper Paleozoic rocks; available evidence suggests that the fault at this locality is a steeply west-dipping thrust that may be rooted in basement rocks. Southeastward the basal rocks of the thrust plate are Middle and Upper Cambrian carbonates and the fault is relatively flat. One large outlier, the CP thrust, is in the CP Hills southwest of Yucca Flat. Six other outliers are distributed over a distance of 75 miles along north-trending axes of major synclines, as much as 35 miles southeast of a possible “root zone” west of Yucca Flat.
The zone below the CP thrust locally is strongly sheared, folded, and faulted. Local blocks of para-autochthonous Devonian and Silurian carbonates were detached from the upper part of the autochthonous block and thrust south-eastward over relatively undeformed Mississippian and Pennsylvanian rocks. Southwest of Yucca Flat this subsidiary system is named the Mine Mountain thrust; individual segments of it occur discontinuously beneath the CP thrust.
A major thrust in the Specter Range may be part of this thrust system at a structural level between the root zone and the zone of flat outliers.