Hydrogeothermal studies across the Pecos River Valley, southeastern New Mexico

Heat-flow values calculated along a profile in southeast New Mexico are used to study the regional ground-water flow pattern. The west-east profile extends from the Sacramento Mountains, across the southern part of the Roswell artesian basin, to the New Mexico–Texas border. The heat-flow data are generally calculated from bottom-hole temperatures estimated at various depths, and are therefore thought to reflect depth-dependent anomalies (principally ground-water flow). Two major positive heat-flow anomalies, interpreted to indicate upward ground-water flow, are present along the profile. A narrow anomaly in the western part of the profile is consistent with upward ground-water movement along the western boundary of a buried Precambrian horst. A rather broad anomaly in the middle of the profile appears to be associated with cross-formational flow and discharge to the Pecos River. Both anomalies may be associated with upward flow from depths of 915 or 1220 m and possibly 1524 m in the western region, but probably not deeper than 1829 m. Vertical ground-water flow appears to be absent just east of the Mescalero Ridge; farther east on the High Plains, the data are generally consistent with downward ground-water flow at depths of 610–1220 or 1524 m.