A complex history of interrelated deformation, regional metamorphism, and intrusion characterizes the Deep Creek Range in Utah and the Kern Mountains and northernmost part of the Snake Range in Nevada. The events occurred in a time-variable but thermally continuous sequence, which began with the formation of paracrystalline thrusts, folds, and minor structures at depth and ended with decollement movement across the crystalline mass created earlier.

The oldest structure is a north-trending anticline that developed in the Deep Creek Range during early synkinematic metamorphism. All the inclined pre-Pennsylvanian beds of the southern Deep Creek Range are in the western limb, and metamorphic trends cross these beds in the southernmost part of the range. The folding was associated with east-west thrusting parallel with both structural and metamorphic trends, and both folding and thrusting were followed by a postkinematic crystallization of higher grade minerals. Thrusts parallel with bedding, transverse faults, and minor folds in the basal part of an overlying nonmetamorphic succession were contemporaneous with the deeper metamorphic structures.

In the Kern Mountains and northern Snake Range a similar deformational and metamorphic history is delineated by lamprophyre bodies which intruded a marble during the early synkinematic period. The marble is correlated with Cambro-Ordovician sedimentary rocks. The original thickness was reduced greatly and most of the original lithology was destroyed by major shearing and recrystallization that preceded lamprophyre emplacement. The lamprophyre bodies were amphibolized by postkinematic metamorphism.

After the postkinematic period, the rocks of the southern Deep Creek Range were recumbently cross-folded (N85°E). This major folding parallels the older transverse metamorphic trends. Within the Ordovician to Mississippian sedimentary succession, transversely crumpled thrust plates, major folds, folded thrust planes, and two extensive crush-breccia units were developed.

All the deformation and metamorphism occurred within a substratum across which later moved a major sole thrust, the Snake Range decollement. The movement of the upper plate was toward the east (108°). This thrusting was the last event in the main deformational series. By that time the substratum had become a rigid foundation in which the only synthrust deformation consisted of high-angle faulting and minor thrusting and shearing parallel with the sole plane. Granitic plutons intruded the rocks beneath the thrust, and are sheared by it.

A transverse lineament separates the Deep Creek Range from the Kern Mountains. Structural, stratigraphic, and metamorphic discordance at this lineament resulted from a combination of (1) early north-south folding, (2) development of structurally transverse metamorphic trends, (3) major transverse folding, and (4) creation of lower and upper plate sequences by major movement on the sole thrust.

A cyclic deformational pattern, where compression apparently was followed by tension, is present in the southern Deep Creek Range. This pattern, similar to that described by Nolan in the northern part of the range, is believed to result from a combination of vertical uplift and lateral compression. The considerable strata omission typical of thrusts of this mountain belt possibly results from this combination.