James Badro

2008 James B. Macelwane Medal Winner

Université Pierre et Marie Curie and Institut de Physique du Globe de Paris

James Badro, Emily E. Brodsky, and Diane E. Pataki were awarded the 2008 James B. Macelwane Medal at the AGU Fall Meeting Honors Ceremony, held 17 December 2008 in San Francisco, Calif. The medal is for “significant contributions to the geophysical sciences by a young scientist of outstanding ability.”


It is a great pleasure to introduce James Badro, aka “Jimi,” of the Institut de Physique du Globe de Paris (IPGP), as a recipient of the 2008 AGU James B. Macelwane Medal. Badro is an exemplar of the current generation of mineral physicists, trained in solid-state physics but with an overwhelming desire to bring this expertise to the study of planetary interiors. Jimi credits a college course, “Geology for physicists,” as the trigger for this transition, and indeed his publications faithfully record this geophysical seduction.

Badro’s signature accomplishment has been characterization of the pressure-induced spin-state transition of Fe in ferropericlase and perovskite observed via synchrotron-based, X-ray absorption spectroscopy. The work, presented in two Science papers, describes a fundamental transition in the chemistry of iron influencing the equations-of-state, phase equilibria, elasticity, and transport properties of the oxide mineral phases constituting the majority of the Earth’s lower mantle, and has changed the way we view the deep mantle. These results have spawned a plethora of investigations by other researchers with numerous AGU theme sessions dedicated to associated theoretical and experimental efforts. Badro’s most recent contribution, authored with his postdoc, A.-L. Auzende et al., describes the variation in Fe-Mg exchange and transition metal partitioning between ferropericlase and perovskite as a function of pressure, and clearly demonstrates the effects of the spin-state transition on lower mantle phase equilibria. Along with the discovery of the post-perovskite phase, the spin-state transition in ferropericlase and perovskite constitutes an important new constraint on lower mantle chemistry.

Elasticity and acoustic wave velocities constitute the nexus between mineral physics and seismology. With his colleagues, Badro has applied inelastic X-ray scattering to constrain the collective properties of planetary interiors. Of particular interest are measurements of compressional sound velocities in light element alloys of iron (FeO, FeSi, FeS, and FeS2). Comparison of model velocities/densities derived from these experimental results and seismic models yields a geochemically reasonable inner core with approximately 2 weight percent Si.

Badro’s energy appears boundless, and the same can be said for his enthusiasm for new techniques to interrogate planetary interiors. In this regard, he has been leading the way in the application of focused ion beam (FIB), transmission electron microscopy (TEM), and secondary ion mass spectrometry to chemical characterization of lower mantle mineral assemblages synthesized in the diamond cell. This methodology holds promise for extending experimental geochemistry to the deep Earth.

Early career awards such as the Macelwane Medal recognize outstanding achievements by young scientists but also strive to predict future scientific leadership. There is little doubt that James Badro is a deserving recipient on both counts. Given his outgoing nature, active intellect, and perpetual energy, Badro is sure to be an important player in the study of planetary interiors for years to come, and it is an honor to present him as one of this year’s Macelwane Medal recipients.

—F. J. RYERSON, Lawrence Livermore National Laboratory, Livermore, Calif.


Thank you, Rick, for that splendid citation, and thanks for your kind and generous words.

Let me first extend my gratitude to the nominating committee you put up, and to AGU for endorsing that nomination. It is a great honor to receive the James B. Macelwane Medal.

Frankly, when one looks at the list of previous recipients, and what they went on to achieve, the feeling is clearly overwhelming and almost intimidating. It is also a great incitation to carry on.

I started off as a physics undergraduate at École Normale Supérieure de Lyon, and I would not even be enjoying myself nearly as much as I am now in Earth sciences had I not picked a class called “Geology for physicists”; from that point on, I knew this would be the way I’d follow. One of the professors was Philippe Gillet, who went on to become my Ph.D. advisor. So my first thank-you goes to you, Philippe, for bringing me over to the bright side. Now, I know many of my colleagues are very dissatisfied with my understanding and my mishandling of geochemistry. Please express any complaints to Francis Albarede, who was my geochemistry professor, and another influential character in Lyon. Thank you very much, Francis.

After my degree, I went on to pursue my research as a postdoc at the Carnegie Institution Geophysical Laboratory, in Washington, D. C. I worked mostly under the guidance of Dave Mao. This is where we first started looking at spin transitions under pressure; and I am afraid this will follow me as a trademark for the rest of my career. I want to express my deepest thanks to Dave for that balance between guidance and freedom that I had during my appointment there, and for being such an amazing and visionary mentor. During my stay in Washington we were dozens of postdocs, interacting like a large family. Many of them went on to become successful academics, and are here today, and I want to salute them and thank them for those great years and for their lasting friendship.

I’ve been working in Paris as a researcher at Centre National Recherche Scientifique for almost 9 years now. I am grateful to the organization for the incredible liberty in managing my research and my collaborations; I’d like to salute my colleagues at the Mineralogy Institute and at Institut de Physique du Globe de Paris, with a special mention of my close collaborators during all those years, Guillaume Fiquet and Francois Guyot.

My main external collaboration today is right here in the Bay Area, at Lawrence Livermore National Laboratory. I want to thank my colleagues in Rick Ryerson’s Experimental Geophysics group, who have come in strong numbers tonight, as well as Ian Hutcheon and Peter Weber. It is a great pleasure to work with you folks.

Last, on a day like this I have a special thought for all the younger fellows I was so fortunate to work with during the past few years, whether as graduate students or postdocs; so a big thank-you to Florent Occelli, Anne-Line Auzende, Julien Siebert, Daniele Antonangeli, Alexandre Corgne, and Eugene Gregoryanz.

Once again, let me thank Rick for presiding over the nomination committee, the members of that committee for their support letters, and AGU, for the tremendous honor of receiving the Macelwane Medal.

—JAMES BADRO, Université Pierre et Marie Curie and Institut de Physique du Globe de Paris, France