October 15, 2012
Dr. Varanasi Rama Murthy passed away October 12, 2012. Known simply as Rama to his many friends and colleagues, his career ranged widely with numerous contributions to mantle geochemistry and cosmochemistry as well as to science education. Born July 2, 1933, Rama received his undergraduate training from Andhra University and the Indian School of Mines. He migrated to the United States for his graduate studies resulting in his PhD in Geology from Yale University in 1957. His first postdoctoral studies were on the isotopic composition of meteorites, working with Clair Patterson at Cal Tech to refine the Pb isotope age of the Earth, then with Harold Urey as an Assistant Professor at the newly formed University of California, San Diego on nucleosynthetic anomalies in silver and molybdenum in meteorites and a comparison of samarium, europium and gadolinium isotopic composition between meteorites and Earth rocks to elucidate the role of neutron irradiation in the early solar system.
Moving to his position on the faculty of the University of Minnesota where he stayed from 1965 until his retirement in 2006, Rama's attention turned to chemical and isotopic studies of mantle rocks, a highlight of which is his 1985 Annual Reviews of Earth and Planetary Sciences contribution with Mike Roden on the subject of mantle metasomatism, one of the early expositions on this important process of chemical modification of Earth's interior. On the return of the first Apollo samples, Rama undertook geochronologic and chemical studies of lunar basalts leading to models for the chemical evolution of the Moon (e.g. Rama Murthy et al., Nature 1971).
Following a long term interest in the composition of Earth's core that began with his first paper on the subject in 1970 (Rama Murthy et al., Physics of Earth and Planetary Interiors), Rama is perhaps best known for his suggestion (Science 253, 1991) that the excess siderophile abundances in Earth's mantle might reflect a high-temperature, magma-ocean, formation for the core. In his model, the high-temperature, high-pressure, of this mode of core formation drove metal-silicate partition coefficients of siderophile elements between liquid metal and silicate to lower values than those measured in one atmosphere experiments. This suggestion led to a huge and continuing experimental effort by a number of workers who explored the pressure and temperature dependency of siderophile element partitioning. Rama continued this line of investigations with experimental work of his own withcolleagues at the Geophysical Laboratory to see whether potassium might be soluble in iron metal at high temperature and pressure and thus provide a radioactive heat source inside the core.
While undertaking this active research career, Rama also served a number of administrative roles at the University of Minnesota including the Head of the School of Earth Sciences, Associate Dean and Acting Dean in the Institute of Technology, and Vice Provost and Associate Vice President of Academic Affairs. His generous nature, wide ranging interests, and ability to tell a good story made him a favorite colleague of many and a success in his many academic pursuits. During his career, Rama received numerous awards including election as a Fellow of the AGU, a Life Fellow of the Indian Geophysical Union, and award of the Outstanding Service Award from NASA. Rama retired in 2006 where he continued his scientific pursuits as a Research Professor with the Institute of Meteoritics at the University of New Mexico.