Estimates of terrestrial heat flow in northern Chihuahua, Mexico, based upon petroleum bottom-hole temperatures

Bottom-hole temperature data from deep petroleum tests are used in conjunction with estimated and measured thermal conductivity values to estimate heat flows at 12 sites in northern Chihuahua. The errors and uncertainties associated with these estimates and measurements are discussed. From these heat-flow estimates, several geothermal regions are proposed which appear reasonable in terms of data statistics and the geologic environments. In northeastern Chihuahua, an area of considerable tectonic activity with no Cenozoic volcanic activity, the heat-flow mean is ∼73 mW/m². Westward in north-central Chihuahua, the heat-flow values become ∼85 mW/m². Farther westward, in northwestern Chihuahua, heat flows >∼105 mW/m² are estimated; however, there is only a modest probability that mean heat-flow values for northwestern and north-central Chihuahua differ. Very high heat flows (>∼250 mW/m²) and low heat flows (<∼70 mW/m²) are not observed in north-central or in northwestern Chihuahua. The deep-temperature data may be removed from the effects of hydrothermal activity in sediments and along faults, which can cause very high or low values. It may also be possible that potential magma sources in the crust of the study area are not as young and hot as the sources associated with the volcanics along the Rio Grande rift in New Mexico, although heat flows of >∼105 mW/m² do suggest crustal magmatic sources. Additional geophysical data will be needed to consider these possibilities.