Physical Sciences, Mathematics, Chemistry, Geology
Math and Science Department
OFFICE: Humanities, Room #145
PHONE: 719-384-6845
E-MAIL: Aaron.Reyes@ojc.edu
Research Interests & Background:
My research interest resides in the study of isotope geochemistry to better understand the behavior of isotopic systems in nature. Such knowledge can help provide information regarding spatial and temporal distribution of groundwaters, rock water interaction processes in the saturated and unsaturated zone, and biomass uptake and fractionation of isotopic systems.
Isotopic tools such as 36Cl/35Cl, 14C/12C, 3H/H can be used to place temporal constraints on young water masses (> 35,000years). Similarly, Isotope systems such as 87Sr/86Sr, and 234U/238U can be used to place spatial constraints on water masses. Uranium concentrations and 234U/238U activity ratios are also good redox indicators. I demonstrated in my thesis work that changes in 234U/238U activity ratios in reduced environments occur faster than expected as suggested by former studies in the literature.
I am currently interested in the time scales and rock water interaction processes that control isotopic ratios and their fractionation in nature. What is the time scale for Isotopic systems (say 87Sr/86Sr) flowing in the saturated zone to reach equilibrium with a given rock matrix? How does this process differ in the unsaturated zone? What are the effects of biogenic uptake on such ratios (vadose zone effects)? I am also interested in investigating the use of different isotopic systems to not only trace but to place time constraints on groundwater masses. In my work I dated groundwater masses utilizing two different isotopic systems (3H and 36Cl) obtaining remarkably similar results. I am interested in exploring the possibility of using systems that have worked in the past (such as 3H and 36Cl) to place time constraints on groundwater ages as a control to explore other systems such as 226Ra.
A better understanding of these isotopic systems and their behavior in groundwater may prove to be particularly useful in places were physical hydrological data is scarce or not available. Such systems can be used to develop conceptual chemical groundwater flow models which in turn can be of use for management of water resources.
Aaron O. Reyes
