Chapter 19: Structural unroofing of the central Panamint Mountains, Death Valley region, southeastern California

Greenschist and amphibolite facies metamorphic rocks within the core of the Panamint Mountains of southeastern California were brought to the surface largely by movement on diachronous systems of west-dipping normal faults. Much of the unroofing can be attributed to displacement along the low-angle Harrisburg detachment, which placed weakly to unmetamorphosed upper Precambrian-Paleozoic strata on upper Precambrian metasedimentary rocks in Miocene time, prior to 10.6 ± 0.9 Ma intrusion of the Little Chief quartz monzonite porphyry. The Eastern Panamint normal fault system (late Miocene) initiated at a moderate angle (40 to 60°), juxtaposing amphibolite facies(?) Precambrian crystalline basement and upper Precambrian-Paleozoic sedimentary rocks. Range-scale anticlinal folding of the Harrisburg detachment and eastward tilting of the Eastern Panamint fault system are attributed to reverse-drag flexure induced by movement on the west-dipping Amargosa fault system (late Miocene?), which is exposed in the Black Mountains to the east of Death Valley and is inferred to dip beneath the Panamint Mountains. The low-angle Emigrant detachment (late Miocene to early Pliocene) incised the Harrisburg footwall and acted as the growth fault for the Neogene Nova Basin, which is dominated by material eroded from the metamorphic core.