The late Miocene to Pliocene Silver Peak–Lone Mountain extensional complex in the western Great Basin is part of a structural stepover that links dextral transcurrent motion between the Furnace Creek fault system and northwest-striking transcurrent faults in the central Walker Lane. In the Silver Peak Range, the extensional complex is exposed as a west-northwest–trending turtleback structure that consists of a folded detachment fault separating a metamorphic lower-plate assemblage from unmetamorphosed upper-plate rocks. The upper plate preserves structurally attenuated lower Paleozoic carbonate and clastic rocks, upper Oligocene to lower Miocene volcanic rocks, and a synextensional mid-Miocene to Pliocene clastic and volcanic succession. The three-dimensional geometry of fault-bounded extensional basins formed during displacement on the detachment is preserved, and the synextensional units comprise five sequences separated by unconformities. The locus of deposition migrated spatially as dimensions of small basins changed through time. The entire extensional complex is deformed in two generations of late Cenozoic folds. North-northeast–trending folds formed first with axial traces oriented at a high-angle to upper-plate extension, and these are preferentially developed in proximity to thrusts and partially inverted extensional faults. Younger, west-northwest–trending folds parallel the axis of the turtleback structure and involve all lithologic units, several syndepositional high-angle faults, and the basal detachment. Pliocene growth of west-northwest–trending folds marked the end of slip on the exposed parts of the basal décollement and the cessation of deposition in the fault-bounded basins. Today, upper and lower plates of the extensional complex are dissected by north- to northeast-striking normal faults that cut alluvium and cross-cut and locally reactivate earlier Cenozoic structures.

Cenozoic deposits of the Silver Peak region, western Nevada, and adjacent California consist principally of continental sedimentary and pyroclastic rocks of the Esmeralda Formation and lavas and tuffs of the Silver Peak volcanic center. The sedimentary rocks comprise several thick sequences of tuffaceous volcanic sandstone and siltstone and interbedded air-fall tuff. These rocks were deposited in basins that coincide in a general way with the present valleys. Thick wedges of conglomerate and sandstone occur along the basin margins and reflect source areas. Most of the sedimentary rocks were deposited under fluctuating fluviatile and lacustrine conditions, but paludal conditions prevailed locally. Abrupt facies changes and numerous local unconformities indicate that deposition was not uniform within a given basin. The sedimentary rocks range in age from late Miocene to late Pliocene. The oldest reliably dated rocks in the Esmeralda Formation are 13.1 m.y. by K-Ar (Barstovian), and all sedimentary strata are younger than an ash-flow sheet dated at 21.5 m.y. by K-Ar. An air-fall tuff in the upper part of the section has a K-Ar age of 4.3 m.y. Rocks of the Silver Peak volcanic center, 4.8 to 6.1 m.y. by K-Ar, crop out principally in the central part of the Silver Peak Range. Along the margins of the range, they overlie and interfinger with the various sedimentary sequences. The volcanic rocks are mostly rhyolite and trachyandesite tuffs and flows with subordinate basalts and andesites. Basin and Range faulting began in late early to middle Miocene time and has continued intermittently to the present, but present topography was largely established by late Pliocene time.