THE TURTLEBACKS OF DEATH VALLEY

WHAT IS THEIR ORIGIN?

Along the western flank of the Black Mountains of Death Valley, there are three unique landforms. Curry, the first to desribe these structures, thought that they resembled the carapaces of a land tortoises and he subsequently named the turtlebacks. The Badwater, Copper Canyon, and the Mormon Turtleback all share smooth, convex upward surfaces (resembling domes) with northwest-southeast trends, and core crystalline basement complexes that are overlain by younger metamorphic units. At least five different origins have been proposed for the turtlebacks; regional compression, folding of a regional thrust fault, mullions, intrusion of shallow plutons, or differential erosion.

Structural map of Death Valley region, note the locations of the three turtlebacks.  
Hachured lines mark positions of major normal faults; full arrows show inferred direction of crustal 
extension; half arrows show relative displacement on strike-slip fault zones (Troxel and Wright, 1987).

References:

Holm, Daniel et al. "The Death Valley Turtlebacks reinterpreted as Miocene-Pliocene folds of a major detachment surface. Journal of Geology, v102, p. 718-727, 1994.

Miller, Martin G., 1999, Gravitational reactivation of an extensional fault system, Badwater Turtleback, Death Valley, California. In: Wright, L. A. and Troxel, B.W., eds., Cenozoic Basins of the Death Valley Region: Boulder, Colorado, Geological Society of America Special Paper 333.

Miller, Martin G., 1991, "High-angle origin of the currently low-angle Badwater Turtleback Fault, Death Valley, California." Geology (Boulder) V19, n4, p372-375.

Miller, Martin G., 1999, Implications of ductile strain on the Badwater Turtleback for pre-14-Ma extension in the Death Valley region, California In: Wright, L.A., and Troxel, B.W., eds., Cenozoic Basins of the Death Valley Region: Boulder, Colorado, Geological Society of America Special Paper 333.

Troxel, B. W., and Wright, L. A., 1987, Tertiary extensional features, Death Valley region, eastern California: in Hill, M. L., Ed., Centennial Field Guide, v. 1, Geological Society of America, Cordilleran Section, Boulder, CO.

More references to be added pending interlibrary loans