Mathematical reconstruction of the hydrothermal evolution of the Rio Grande Rift near Socorro, New Mexico during the past 28 million years indicates that fault-block motion controls the position of active and ancient groundwater discharge areas. Two-dimensional finite element models of groundwater flow, heat transfer, and fault block kinematics, constructed along a cross-sectional transect across the rift near Socorro using the program RIFT, indicates that domino-style fault-block motion created “hydrologic windows” in the aquitards shifting the regional discharge area l0 km westward. Basement involvement in inter-basin transfer of both groundwater and heat during basin evolution is also indicated by the model. Active and ancient groundwater flow systems are probably responsible for the present-day thermal anomalies, the potassic alteration of ash flow tuff layers, young fission track age ( ~ 4Ma) of apatite samples collected near Socorro hot springs, and the formation of barite ore minerals in the Gonzales prospect to the east of the Rio Grande River.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah