Young Scientist Award (Donath Medal)
Elizabeth J. Catlos
Oklahoma State University
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Presented to Elizabeth J. Catlos
Citation by T. Mark Harrison
Elizabeth Catlos is a remarkable young scientist who has already made outstanding contributions to geologic knowledge. Her trip to the podium tonight began with the arrival of Bohus and Eva Catlos’ second daughter. Recently arrived political refugees from Czechoslovakia, Liz’s parents instilled the émigrés ethic of hard work and an expectation of rigorous inquiry in their children; high among the qualities that led to this award are her integrity and extraordinary tenacity. With regard to the latter, I should explain that my principal qualification to introduce and praise Elizabeth is that I was her Ph.D. advisor. While Liz was comfortable with me offering her advice, she rarely availed herself of it. Her tenacity and scientific insight were demonstrated during her first graduate research project — the development of an ion microprobe method for dating allanite — a common accessory phase in notoriously difficult-to-date low-grade metasediments. In contrast to dating minerals of simple composition, such as zircon, allanite is a garbage can of variable substitutions and was expected to be difficult to calibrate. This was confirmed by preliminary measurements which indicated unprecedented matrix effects hundreds of times greater than for zircon with no known controls. I felt that continuation of this research was too risky for a beginning graduate student and strongly advised Liz to drop the effort. She respectfully declined, and her steadfastness was rewarded. She sought out and was awarded a predoctoral fellowship to the Smithsonian Institution to access its extensive mineral collection and use its specialized facilities to characterize a compositionally diverse suite of allanites. Her undergraduate specialty in chemistry aided the development of a new model for understanding allanite chemistry and led to the discovery of a relationship between rare earth content and inter-element ionization yields from which a dating method for allanite was developed. This tool permits a number of important problems to be addressed and has been used successfully in a variety of geologic environments. This spirit of perseverance has characterized her remarkable growth as a scientist.
Liz chose to apply her new method to understanding the tectonic evolution of the Main Central Thrust, the feature largely responsible for creation of the Himalayan range. As her field skills were, well, largely that of a chemist, I recommended an easier avenue which she again declined. Liz immersed herself in field courses and volunteered for a three-month stint as field assistant to a structural mapping party in remote northern Tibet. After this experience and two field seasons in the Himalaya, she documented the existence of surprisingly young crystallization ages adjacent the MCT across the length of the mountain range. A common point of departure for the numerous models seeking to account for the classic inverted metamorphic sequences across this fault — high-grade gneisses atop low-grade metasediments — was to assume that the two sequences were causally related through placement of the hot upper plate around 20 million years ago. Liz applied thermobarometric methods to these garnet-bearing rocks and recognized, for the first time, three distinct petrological domains within the Himalaya. Using in situ Th-Pb dating of inclusions in garnet, a method she co-developed, she directly determined the timing of the apparent inverted metamorphism and discovered the extraordinary fact that the structurally lowest domain was undergoing metamorphic recrystallization as recently as 3 million years ago. This work overturned 25 years of Himalayan models that have been widely exported to explain aspects of other orogenic belts and led to a radically different view of the evolution of the Himalaya. The picture that emerges is of continuous Himalayan convergence being manifested as out-of-sequence thrusting and intermittent magmatism while creating geological relationships with a high potential for imparting misleading clues. In terms of importance of petrologic problems based in the continental crust and applicable to understanding dynamic crustal processes, only a few of her peers can match this record of discovery.
Liz teamed up again with Sorena Sorensen at the Smithsonian to obtain quantitative timescales of aqueous fluid cycling in subduction zones. Using a clever scheme tying the addition of water to incorporation of large-ion lithophile elements during high pressure/temperature metamorphism and then coupling this to 40Ar/39Ar dating, she deduced timescales of between 25 and 60 million years for fluid-rock interaction in two subduction complexes. This work, published in Science, is further evidence of her thoughtful and original approach to addressing important and longstanding problems in earth science. As she undertook the dating in my laboratory, she of course first explained to me what the goals of her study were. I suppose I don’t have to tell you what my advice to her was.
Liz has recently expanded her research along the Alpine-Himalayan chain and is using this opportunity to foster excellence in undergraduate research at her home institution, Oklahoma State University. She is a talented young scientist, a wonderful role model, and a deserving recipient of the 2006 Donath medal. It is with enormous pleasure that I introduce to you Elizabeth Catlos.
2006 Donath Medal - Response by Elizabeth J. Catlos
I am very happy to be here today to receive the Donath Medal. Where I stand now in my career is possible because of twists of fate and circumstance, but overall because I am doing what I love, and that is geology.
I want to first thank Mark Harrison, my advisor, role model, and mentor. His influence on my life and career is enormous. I came to UCLA with a Bachelor’s degree in chemistry and only 5 undergraduate classes in geology. I owe a great debt of gratitude to Mark and to the faculty in UCLA’s Department of Earth and Space Sciences for teaching me the basics of geology. Mark steered my Ph.D., taught me the basics of isotope geochemistry, and allowed me the freedom to explore my interests. I know that my life would be different had it not been for Mark and his vision. He may have told me to drop my focus on certain projects, but I always saw that advice as re-prioritizing goals.
My first project at UCLA was to develop an ion microprobe method to date allanite. This mineral is called a garbage can by most geologists I know. But as a chemist, I saw it as just too friendly to all of the elements in the periodic table. When our initial attempts at dating the mineral failed, I don’t remember Mark telling me not to continue. I do remember him opening drawers outside his office, showing me 76 rocks from the Himalayas, and saying, this is your new project. That was the beginning of my research in the Himalayas, and Mark and I were part of a team that discovered the reactivation of a large-scale thrust in the range. Those 76 rocks were the foundation for new ideas about mechanisms involved during continental collision.
The allanite project lived on because of advice I was given by Marty Grove. Marty had confidence in me and that the dating method could work. He suggested that I contact Sorena Sorensen. I thank her for her mentorship and support. The most important perspective that I learned from Sorena is to begin with a firm understanding of mineral chemistry. We worked together for a summer at the Smithsonian Institution and when I returned to UCLA, I was given one day on the ion microprobe to see if the dating method would work. It did. After my Ph.D., Sorena contacted me about another idea: could we understand the timescale of fluid-rock interactions in subduction zones by dating barium-rich phengites? Marty Grove was instrumental on this project as well, and helped us with the basics of argon dating. Phengite was another mineral that was considered not ideal due to its propensity for excess argon. We again relied on our conviction that if we understood the basics of phengite chemistry, we could apply its ages to understand geologic problems.
I want to thank An Yin and Craig Manning, who were part of my Ph.D. committee at UCLA. They taught me the principles of field geology and developed my research skills. They helped me focus what seemed like an insurmountable amount of data into coherent ideas and models. An’s mantra of “Just do it!” is one that I tell my students.
I also would like to thank Bill Carlson, Jack Cheney, John Ferry, Karen McBride, Frank Spear, and Matt Kohn, who supported my nomination for the Donath Medal as well as other pursuits. Matt taught me how to use an electron microprobe. I now have 2 electron microprobes in my lab, generously donated by ConocoPhillips. During my Ph.D., Matt and I worked together in the Himalayas. At Oklahoma State, Ibrahim Cemen suggested that we apply the principles we developed to understand collision to settings characterized by extension. Today, we conduct National Science Foundation supported research in Western Turkey and had an exciting field season with Cemal Goncuoglu and Mete Hancer.
I want to thank my Indian colleague and mentor, Chandra Shekhar Dubey. We conducted NSF-supported research in the Himalayas with Richard Marston, where I learned to appreciate connections between geomorphology and tectonics. Through Dubey, I was able to meet A.S. Janardhan who introduced me to the geology of the Southern Granulite Terrain in South India. Janardhan passed away in November of 2004, and an Indian newspaper wrote that his demise is a loss to the country. It was a loss to me as well.
I want to thank those who have supported my research program: the National Science Foundation and administrators at Oklahoma State, specifically those in the Vice President for Research Office and College of Arts and Sciences. My research is possible because of UCLA’s National Ion Microprobe facility.
I thank my family for their support. My grandmother passed away on July 4 of this year. She graduated from medical school in Czechoslovakia in 1938. She survived World War II, but her husband, her parents, and her sister were killed. In 1968, she immigrated to the US, and, at the age of 54, learned English, how to drive a car, passed all board medical tests, and began her own practice. My parents had escaped Czechoslovakia in 1966 and came to the US with nothing but their education. My mother is a doctor and my father is an engineer. My father sparked my interest in science at a young age.
In closing, I thank the Donath family for this honor.