New Mexico Geological Society Annual Spring Meeting — Abstracts

Groundwater monitoring well, Coyote Test Field-Monitoring Well 2 (CTF-MW2), is located on Kirtland Air Force Base in Albuquerque, New Mexico and is part of Sandia National Laboratories (SNL) Groundwater Monitoring Program. The well was installed in 2001 as part of an investigation on the potential release from a wastewater system. The borehole was advanced to 190 feet (ft) below ground surface (bgs). During installation, fault breccia was possibly encountered at 145 ft. The well was installed to 135 ft with a screened interval from 110 to 130 ft. CTF-MW2 is also located approximately 1,000 ft east of the Tijeras Fault. Previous analysis of the well revealed bicarbonate alkalinity, along with high calcium, sodium, and arsenic values. The distinct geochemical signature suggests that the fault is allowing an abundance of carbon dioxide (CO2) to influence the groundwater that results in an increase in calcium, sodium, and arsenic. This necessitates that there is a distinct geochemical signature for the groundwater. A noble gas analysis has shown that there is a mantle component to the CO2 and that combined geochemistry and gas analysis show the mixing of epigenic and endogenic waters.