Continental Tectonics
We use the isotope geochemistry of modern systems such as gas-rich hot springs and the record of past fluid-rock interaction such as mineralization in faults to understand the role that deeply-circulated and sourced geofluids play in active tectonics. New, active and recent research projects:
Collaborative Research: RAPID: Fault rock and spring sampling of the 2023 Kahramanmaraş, Turkey, earthquake sequence ruptures (NSF-Tectonics - 2335077: PI Ault, Co-PI Newell, Co-PI Akciz - CSU Fullerton). Collection of time-sensitive samples of fault rocks, spring gases, and CO2 flux measurements associated with the devastating earthquake sequence in Turkey in the spring of 2023. Collaborative Research: Mantle to crust fluid transfer in an active flat-slab subduction zone - insights from Peruvian thermal spring geochemistry (NSF-1623034, in collaboration with M. Jessup, Univ. of TN Knoxville). We are using aqueous and isotope geochemistry of hot springs in Peru to map the distribution of mantle and crustal volatiles above a flat-slab subduction zone. We are also characterizing the microbiology of these hot springs, quantifying links between geochemistry, temperature, and the microbial community. Collaborative Research – Quantifying crustal hydration effects in the Colorado Plateau from xenoliths (NSF-1937347, in collaboration with K. Mahan, CU Boulder). Our research group will focus on the stable isotope geochemistry of hydrous mineral phases in xenoliths to constrain the fluid types present during crustal hydration. EAGER - Mantle fluid contribution to springs along the Denali Fault System (NSF-216338 in collaboration with Sean Regan UAK Fairbanks). This new pilot study will use helium isotopes in mineral springs along the Denali Fault and associated strands to interrogate their crustal scale nature and connectivity. |
Low Temperature Geochemistry
Research that falls into the general theme of "low temperature geochemistry" uses stable isotopes and major/trace elemental chemistry to interrogate fluid-mineral-biosphere interactions that record past and present environmental and hydrological conditions.
Collaborative Research: Quantifying watershed dynamics in snow-dominated mountainous karst watersheds using hybrid physical based and deep learning models (NSF-2043363). This new collaboration with Bethany Neilson (USU), Tianfang Xu (ASU), and James McNamara (Boise State) will use a multidisciplinary approach to understand and model the hydrology of mountainous karst watersheds, using the Logan River basin as the study focus. Iron oxide concretions in the Colorado Plateau. Iron oxide concretions are common in the sandstone units (e.g. Navajo Sandstone) of the Colorado Plateau and have been the target of many studies. However, hypotheses on their formation vary significantly. We are currently using O and Fe stable isotopes to investigate the formation of Fe-oxide concretions and "pipes" northwest of Moab, UT. Great Salt Lake microbialite isotope geochemistry and chronology. We are investigating the diverse microbialite deposits in GSL using stable isotopes and geochronological techniques (radiocarbon and U-Th). Like other lacustrine carbonates, the these deposits may record information about past lake level fluctuations, salinity, and biogeochemistry. |
Energy Geosciences
We apply stable isotope and other geochemical tools to address societally relevant problems in the broad field of "energy geosciences." Currently, we focus on alternative energy solutions and mitigation measures of global climate change.
Geothermal energy exploration in the Snake River Plain (SRP). USU (PI Shervais) has managed two DOE funded exploration efforts in the SRP (Project Hotspot; Play Fairway Analysis of Camas Prairie). These projects have integrated field mapping and sampling, geophysical surveys, exploration drilling, and numerical modeling. My group has been involved in the stable isotope and geochemical analyses of modern fluids (groundwater, hot and cold springs) and recovered drill core. Our work aims to characterize fluid sources and compositions, and estimate the temperature of geothermal reservoir fluids (geothermometry). Geological carbon sequestration. Collaborative research on this topic has used experimental and natural analog studies to understand how injected CO2 with interact with subsurface fluids and minerals. Experiments have examined the interaction of supercritical (sc) CO2 in wellbore environments, CO2-water-mineral equilibria, and the dynamics of scCO2 dissolution and mixing into brine, possible impacts of CO2 injection on groundwater quality, and environmental monitoring. Natural analog studies have targeted the isotope and aqueous geochemistry of CO2-rich hot and cold springs as proxies for leaky sequestration reservoirs and impacts to shallow groundwater chemistry. |