Geophysics, geology, and geothermal leasing status of the Lightning Dock KGRA, Animas Valley, New Mexico
— Christian S. Smith

Four stock wells drilled in sec. 7, T.25S., R.19W., Animas Valley, New Mexico in 1948 hit steam and boiling water at depths of less than 30 m. The wells tapped water and steam at 101.5°C from a zone of alluvium 5-10 m thick which overlies a lithic rhyolitic tuff. These wells are referred to as "hot wells." There are no other surface manifestations of an active hydrothermal system in the Animas Valley.

The hot wells have prompted the geothermal industry to file both competitive and noncompetitive lease applications for rights to the geothermal resource in the Animas Valley. The Geothermal Steam Act of 1970 specifies that where areas of sections included within more than one lease application overlap by more than 50 percent, the overlapped area is designated a Known Geothermal Resource Area (KGRA) (fig. 1). This area has been denoted the Lightning Dock KG RA; Lightning Dock Mountain is a nearby peak in the Pyramid Mountains.

This article presents geophysical and geologic data collected in the area and attemptes to show that geologic features caused by superimposed but unrelated tectonic events control the occurrence of hot water. It also briefly discusses the interest and activity of the geothermal industry in the area.