The DF 62-21 well is located near the middle of Dixie Valley about 10 km due east of the 66-21 well and about 4 km southeast of the Dixie Valley Production Field. This well is 3810 m (12,500 ft) deep, penetrating a sequence of basin-fill deposits, Tertiary tuffs, Jurassic gabbro and Triassic shale/slate. The bottom hole temperature is 184°C and a fluid entry occurs at 2900 m at the contact of gabbro and underlying Triassic slate. When opened the well eventually flows 140 l/min of water at about 76°C. No free gas was observed associated with this water in May 1998.
DF 62-21 water contains moderate amounts of SiO2, Br, and Li, and high contents of As and B. Concentrations of Ca and Mg are low but the Cl content is only about 80 ppm. This water does not resemble the Dixie production brines, but does resemble Hyder Hot Spring water both chemically and isotopically (oxygen-18 shift of 1.5‰). Interestingly, DF 62-21 water contains 0.83 T.U. tritium (more than most of the hot springs) suggesting it is a mixed fluid. Overall, DF 62-21 water has characteristics of moderate-temperature geothermal fluids. Chemical geothermometers suggest equilibration at temperatures ≤150°C, possibly around 135°C (Goff et al., 2002).¡± (Blackwell et al., 2006 (in review))