Mid-Tertiary arcuate dikes and faults of the Rio Hondo-Red River drainages, Sangre de Cristo Mountains, New Mexico: A postulated outlying ring-fracture zone to the Miocene Questa caldera

Arcuate faults, dikes and the distribution of base and precious metals occurrences along the Red River and Rio Hondo drainages of northern New Mexico define an integrated mid-Tertiary structural break. This break represents a ring-fracture zone which exhibits normal displacement down to the north in the direction of the 26 Ma Questa caldera; movement along the fault zone is bracketed between 26-21 Ma. The ring-fracture zone defines a previously unidentified outlying structural boundary to the Questa caldera.