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My first real exposure to geology came while serving as a high school volunteer for the Student Conservation Association at Zion National Park. After spending two summers working as a field assistant in northern New Mexico for a geology professor at Williams College, I decided to change my major to geology. I headed west to graduate school at Stanford University, where I did field mapping and laboratory investigations of the Los Azufres geothermal field in Mexico and a detailed petrologic study of boninite series volcanic rocks from their type locality in the Bonin Islands of Japan.
I spent three years as a postdoctoral fellow at Caltech, where I was introduced into the world of experimental petrology. After a brief stint as a postdoc at UC Santa Barbara, I then moved to Unocal's Hartley Research Center, where I ran the stable isotope laboratory. I then transferred to Unocal's Geothermal Division, where I was involved in the exploration of geothermal systems in Indonesia, Central America, and South America.
I joined the Earth Sciences Division of LBNL in 2000, and have been involved in a variety of geologic and geochemical research projects. I led LBNL's efforts in the study of the Peña Blanca uranium deposits, a natural analogue for flow and transport processes at Yucca Mountain. From 2007 to 2009, I served as a detailee for the Geosciences Research Program of DOE's Office of Basic Energy Sciences. I am currently a member of the DOE Geothermal Technologies Program Technical Monitoring team.
I have worked on a number of field, laboratory, and modeling studies during my career. Much of my work has involved the study of volcanic rocks and the effects of water-rock interaction. My masters thesis examined the volcanic stratigraphy and geochemistry of the Los Azufres geothermal system in central Mexico. For my dissertation, I studied the petrogenesis of boninite rocks from their type locality in the Bonin Islands, Japan. My postdoctoral work involved an experimental determination of the fractionation factor for hydrogen isotopes between water and natural and synthetic glasses at elevated temperatures.
During my professional career, I have continued working on geologic problems associated with water-rock interaction. I used stable isotope geochemistry to examine diagenesis in sedimentary rocks and to monitor changes in fluid and rock chemistry in a number of geothermal systems at Unocal's Hartley Research Center. While working for Unocal's Geothermal Division, I was a member of an interdisciplinary team that integrated geologic, geochemical, geophysical, and reservoir engineering data to develop conceptual models used to evaluate geothermal prospects and select exploration drilling targets for geothermal systems around the globe.
While at LBNL, I have been involved in a variety of geologic studies. I studied geothermal systems such as Yellowstone and the Nopal I uranium deposit in Mexico as analogues to geologic processes expected to be of importance at the proposed high-level radioactive waste repository at Yucca Mountain, Nevada. Field observations and laboratory measurements of water and rock samples collected from these analogues, along with measurements obtained from a laboratory experiment examining water-rock interaction and boiling in a single fracture, were used to constrain numerical simulations of coupled processes involving fluid flow and water-rock interaction in fractured rocks. I am currently involved in field and coupled process modeling studies of The Geysers and other geothermal systems. IIn collaboration with colleagues at LBNL and the University of Chile, I am conducting a study of helium isotopes in geothermal systems in Chile to examine the effects of crustal thickness, volcanism, and regional faulting on geothermal fluid compositions.