MAPPING CRUSTAL DEFORMATION USING SEISMIC ANISOTROPY, RUBY MOUNTAINS, NEVADA

Metamorphic core complexes are surface exposures of the deep crust commonly associated with high-magnitude extension. The mechanics of metamorphic core complex formation are uncertain with considerable debate as to how these structures form. This research focuses on examining the mid- to lower-crustal expression of these features. This is accomplished using receiver functions calculated from broadband seismic data to identify crustal anisotropy and estimate strain beneath the Ruby Mountains, a large Cordilleran-type metamorphic core complex in northeastern Nevada. Anisotropic zones located in the mid to lower crust oriented perpendicular to the range and parallel to the extension were identified beneath the Ruby Mountain. The anisotropic fabric, used as a proxy for deformation, illustrate structures could represent either a low-angle detachment fault or crustal flow. Our observations are consistent with two models of core complex formation: the detachment zone model and the mid-crustal flow model.