Earth and Planetary Sciences ETDs

Publication Date

Summer 12-16-2023


The 1.2 Ma Valles Caldera in north-central New Mexico hosts a young igneous volcanic hydrothermal system after the model proposed in Goff and Janik (2000). The Sulphur Springs area within Valles Caldera is an acid-sulfate area typical of this model, discharging acidic waters (pH 1.5-3) formed by oxidation of magmatic H2S at the surface. We report on samples obtained from springs and streams collected between October 2021 and May 2023 in the Sulphur Creek and Alamo watersheds. Sulphur Creek receives input from Sulphur Springs and exhibits low pH (2-4) and high concentrations of Al (≤110 mg/L), Fe (≤60 mg/L) and sulfate (≤1300 mg/L). These hydrothermal components are significantly attenuated by the downstream extent of the field area. This investigation uses geochemical tracers such as major ions, stable and radiogenic isotopes to identify processes controlling attenuation. This research has significance for the continued use of geothermally-affected watersheds as water resources.

Degree Name

Earth and Planetary Sciences

Level of Degree


Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Dr. Laura Crossey

Second Committee Member

Dr. Tobias Fischer

Third Committee Member

Dr. Ricardo González-Pinzón

Fourth Committee Member

Dr. Karl Karlstrom

Project Sponsors

New Mexico Water Resources Research Institute, New Mexico Geological Society, Geological Society of America, UNM Center for Water and the Environment




geochemistry, geology, volcanology, water quality, acid-sulfate, acidity, metals, Valles Caldera

Document Type