MID-LATE PALEOZOIC DEFORMATION on BUCK MOUNTAIN, WHITE PINE COUNTY, NEVADA

New detailed structural mapping of the strata capping Buck Mountain in White Pine Co., Nevada, has documented two distinct episodes of deformation. The structures and angular unconformities at Buck Mountain are consistent with late-Paleozoic deformation and regional scale unconformities documented elsewhere in northern and central Nevada.

Deformation developed in the Morrowan Ely Limestone is erosionally truncated and depositionally overlain by the mid-Desmoinesian Hogan formation. This deformation in the Ely formation consists of close, west-vergent folds gently plunging ~12° to the southwest (202°) on the northern and western flanks of Buck Mountain. This geometry changes to open, upright, symmetric folds on the eastern and southern flanks of Buck Mountain.

The macroscopic fold at Buck Mountain is developed in both the Hogan and Strathearn formations. It is a gentle to open, symmetric, upright, cylindrical fold plunging ~15° to the northwest (323°) with a wavelength of 1 km and amplitude ~35 meters. This fold has symmetric dips on both limbs (~40¢ª). The age of this fold is unconstrained at Buck Mountain, but it is correlated with Mesozoic folds in adjacent ranges.

The mid-Pennsylvanian deformation at Buck Mountain is important because it: 1) correlates well to other sub-C5 deformation in eastern Nevada, 2) helps constrain the orientation of the regional Pennsylvanian deformation, and 3) displays a regional eastward decrease in intensity of Pennsylvanian deformation.