Graduate student wades into groundwater debate
Outside the Box > > Dennis Newell
By Steve Carr
|Dennis and Trish Newell sample active gases in the Grand Canyon. Photo by Laura Crossey.
UNM graduate student Dennis Newell is interested in the quality of groundwater and origin of contaminants that impact its purity. He is studying the travertine-depositing springs along the Rio Grande Valley from Socorro north to the Colorado border. His research is supported by the New Mexico Water Resources Research Institute at New Mexico State and the National Science Foundation IGERT program.
“Travertine is essentially the ‘lava’ from a chemical volcano, formed by degassing of spring water and chemical precipitation of travertine,” Newell said. “It’s often very beautiful and used as building stone.”
Newell and faculty advisor Professor Laura Crossey of Earth and Planetary Sciences hope to shed light on the origin of poor quality groundwater in aquifers, an ongoing debate in the research community. Newell is inspired by Crossey’s work. It provided a springboard for his research.
“She conducted similar research with colleagues in the Grand Canyon,” Newell said. “She was intrigued by the huge volumes of travertine in the Grand Canyon and began investigating the chemistry of travertine-depositing springs. She discovered that the chemistry of these springs told a very interesting story about the mixing of very deep fluids with shallow groundwater.”
The Rio Grande Valley is an excellent location to test the hypotheses developed in the Grand Canyon, but in a very different geological setting, he said.
Newell is testing water and gas samples. He collected and analyzed 29 samples from spring locations ranging in temperature from 6 – 57°C. Most springs were located along major faults in the region.
Newell hopes to show that travertine-depositing springs are actually ‘windows’ to investigating groundwater-mixing processes occurring within the ancient rocks buried deep along the Rio Grande Valley. He and Crossey hypothesize that travertine-depositing springs in the valley are linked to deeply circulating fluids associated with mantle magmatism deep inside the Earth. They believe that as the geochemistry varies along spring locations, so does the salinity and trace metals present in aquifers and surface water. Newell thinks the fluids are moving along fault systems.
Newell, who has a B.S. in geology from New Mexico Tech and master’s in geology from Colorado State, started his Ph.D. at UNM in the summer of 2003 and will complete his dissertation in about two years.