THE ROLE OF THE ~ 16 -5 MA KNOLL- EAST HUMBOLDT-RUBY MOUNTAINS FAULT SYSTEM IN THE EVOLUTION OF THE RUBY–EAST HUMBOLDT-WOOD HILLS METAMORPHIC CORE COMPLEX, NORTHEAST NEVADA
New tephrochronology from synextensional basin fill and geologic mapping of the Knoll Mountain segment of the Knoll-East Humboldt Ruby fault system reveals that the fault system as a whole was active from 17-16 to 8 - 5 Ma and involved the development of a late-stage, segmented intrabasin fault system between ~8 and 5 Ma. Moreover, the footwall of the Knoll-East Humboldt Ruby-fault system formed a regional horst bounded on the east by the coeval east-dipping Thousand Springs fault system.
In summary, our synthesis indicates that the Ruby-East Humboldt detachment extended well beyond the confines of the core complex as part of the Knoll-Ruby-East Humboldt fault system whereby the central part of the fault system facilitated exhumation of metamorphic rocks in the core complex. Furthermore, this fault system was active for a longer time than previously recognized. Specifically, our data and synthesis indicates that the Knoll-Ruby-East Humboldt fault system and intrabasin faults, at least north of the Ruby Mountains, ceased to be active sometime after 8 Ma but before 5 to 3 Ma.