Dr. Peter Roeder (1932-2014)
Dr. Roeder working in his lab
Peter L. Roeder died on June 7, 2014 in Kingston, Ontario Canada near Queen’s University where he spent most of his career. Peter Roeder was admired as a role model for many students and colleagues, and as a teacher of geochemistry, igneous petrology, and optical mineralogy. As a researcher, Peter was best known for his work in experimental petrology. Peter’s seminal work on olivine-liquid equilibria published in 1970  was a culmination of his previous work in simpler iron-bearing systems. This paper has been cited more than 2000 times, more than 60 times in 2013, which is remarkable for a paper written 44 years ago. The KD approach, laid out in that paper as a simple and elegant expression of the Fo-Fa melting loop in complex systems, provided a powerful tool to evaluate the origin and evolution of terrestrial and extraterrestrial basaltic magmas. This work led the way for the calibration and utilization of many other crystal-liquid KD’s to unravel the compositional evolution of magmas, including Kilauea, in a quantitative and predictive way .
Peter won the Past President’s Medal for Research Excellence from the Mineralogical Association of Canada in 1987. He was Vice-President of MAC from 1990-92 and President from 1992-1994. A special issue of Canadian Mineralogist titled "PHASE EQUILIBRIA IN BASALTIC SYSTEMS: A TRIBUTE TO PETER L. ROEDER" was published in 2001. Peter continued his interest in geochemistry after becoming an emeritus professor in 1996 and was co-authoring papers as recently as 2006.
Peter grew up in Massachusetts, where his father, Kenneth D. Roeder was a world-famous biologist at Tufts and a particularly influential role model, although Peter liked to tell us how at a young age he fancied a future as a professional bait-caster, and fishing remained a lifelong hobby. He also told the story of how during the Korean conflict, he was stationed in San Francisco, where a local gentlemen’s club allowed young soldiers to use its library. Peter, who had recently graduated from Tufts University with a B.Sc. in Geology, took advantage of this offer and it was there that he discovered Bowen’s “The Evolution of the Igneous Rocks.” Entranced by the rigor of Bowen’s approach to fractional crystallization, he decided then and there to pursue graduate studies in experimental petrology at Pennsylvania State University. Professors O.F. Tuttle and E.F. Osborn at Pennsylvania State University had both worked with Bowen at the Geophysical Laboratory and Peter started experimental work on phase equilibrium in simple systems under the supervision of E.F. Osborn. After graduating from Penn State in 1960, Peter held a postdoctoral fellowship at the New Mexico Institute of Technology, before joining the faculty at Queen’s University in Kingston (Bowen’s alma mater).
Peter was predeceased by his loving wife Claire Marie in 2001. He is survived by their three children (David, Katherine and Tina) and four grandchildren, his sister Stephanie and friend Ann Mackenzie.
 Roeder, P.L. & Emslie, R.F. (1970): Olivine–liquid equilibrium. Contrib. Mineral. Petrol. 29, 275-289.
 Roeder, P., E. Gofton, & C. Thornber (2006), Cotectic proportions of olivine and spinel in olivine-tholeiitic basalt and evaluation of pre-eruptive processes, J. Petrol., 47(5), 883–900