Staff and students in the Environmental Isotope Laboratory employ naturally-occurring stable and radioactive isotopes as well as major and trace element compositions in research into a variety of questions in the fields of hydrology, ecology, paleoclimate and geology.
We are honored to continue traditions established by the founders of this lab, the late Professors Austin Long and Paul Damon.
Study areas have historically spanned the globe. Research problems include locations and extent of groundwater recharge, paleohydrology and paleoelevation of evolving mountain ranges, sources of sedimentary basin brines, past solar activity inferred from high-precision radiocarbon measurement on tree rings, origin and evolution of evaporites, methods development in isotope paleohydrology and paleosalinity studies, and extensive work in isotope dendrochronology and isotope studies of cactus spines (acanthochronology).
Recent hydrologeologic studies have revealed sites of recharge in Tucson Basin, and the extent of migration of 1960s precipitation in local aquifers. The sources of municipal groundwater supplies in El Paso and Ciudad Juarez have been established, and the isotope effect of large reservoirs has been used in conjunction with groundwater flow modeling to map recharge beneath the Rio Grande. Tritium in precipitation in southwestern North America has been mapped, and the future usefulness of tritium in groundwater studies has been evaluated.
Stable isotope research in ecology, biology, and climatology include studies of natal habitat and life history for endemic fish in the Gulf of California, pre-dam salinity and flow conditions of the Colorado River and its delta, sourcing marine shell from archaeological settings in the southwest, bird and human migration, the pre-human-impact status of river systems, and the use of saguaro spine geochemistry as a record of past rainfall.
Research facilities in the Environmental Isotope Laboratory include a conventional radiocarbon dating laboratory capable of high-precision analyses, a tritium analysis laboratory for natural environmental levels of tritium, and four stable isotope mass spectrometers equipped for analysis of C,H, N, O and S isotopes in a variety of geological, hydrological and biological materials. Additional equipment associated with the lab includes a LGR laser system for analysis of O and H isotopes in water, two micromilling systems, and a cathodoluminescence microscope unit.
David Dettman, Director, Research Scientist
Christopher J. Eastoe, Co-director, Staff Scientist (Retired)
Typically three or four undergraduate and graduate students are in residence and participating in research.