Chemistry, origin, and potential of geothermal resources of southwestern New Mexico and southeastern Arizona
— Chandler A. Swanberg

The author has visited nearly all of the hot springs in Arizona and New Mexico, recorded the temperature and collected samples for chemical analysis. In addition, the chemistry of several thousand non-thermal ground waters have been used to establish background chemistry for comparison against thermal water chemistry. Standard methods of quantitative and qualitative geothermometry (see Truesdell, 1975 for a summary of techniques) have been applied to all waters and the resulting geotemperatures used to predict the subsurface temperature anticipated for each geothermal prospect area. The most promising geothermal areas are designated in Figure 1. Table 1 contains the chemistry of selected thermal waters from southwestern New Mexico and southeastern Arizona.

On the basis of chemical geothermometry, there appear to be 10 to 20 geothermal prospect areas in southwestern New Mexico and southeastern Arizona whose reservoir base-temperature approaches the 150°C minimum for economic generation of electricity. The most promising of these prospect areas are either associated with Quaternary volcanic rocks or are located along the margins of the deepest sedimentary basins. The thermal waters tend to be slightly saline (1000-3000 mg/k) and enriched in silica and fluoride. The numerous hot spring areas in the Gila National Forest of southwestern New Mexico do not appear to have a sufficiently high reservoir base temperature for electricity generation. However, the low salinity (<500 mg/Q) and high surface-discharge temperature (up to 75°C) of these hot springs make them ideal for non-electric applications.