For sustained contributions on the age, origin and evolution of the continental upper mantle.

Graham Pearson and Mary R. Reid received the 2019 Norman L. Bowen Award at AGU’s Fall Meeting 2019, held 9–13 December in San Francisco, Calif. The award recognizes “outstanding contributions to the fields of volcanology, geochemistry, and petrology.”  

Graham Pearson merits the 2019 Norman L. Bowen Award for adding to our fundamental understanding of igneous processes in the upper mantle through studies of volcanic rocks, exhumed mantle sections, subcontinental mantle samples, and diamonds and their inclusions. Pearson has tackled the major topics in mantle geochemical evolution with a research tool kit that ranges from petrography, mineralogy, and petrology through stable isotopes, radiogenic isotopes, siderophile elements, and spectroscopy. In using these techniques, Pearson has sought new analytical method developments that push the frontiers of analytical sensitivity and precision.

Colleagues will remember a long list of discoveries: large pieces of Earth’s mantle emplaced from the diamond stability field; eclogite xenoliths in kimberlite as Archean subducted oceanic crust; continental mantle keel age-match with overlying crust; Re-Os sulfide age-dating of single sulfide inclusions in diamond; kimberlite derivation from unique mantle sources; the Os isotopic imprint in the oceanic mantle of continental crust extraction; trace element abundances in gem diamonds and source fingerprinting; a modern subduction analogue for Archean craton formation; and the finding, in a superdeep diamond, of the first terrestrial ringwoodite.

In this latter accomplishment, we see a typical example of why Graham Pearson is especially deserving of the Bowen Award. He led the effort to successfully measure the water content of a delicately metastable single grain of ringwoodite while it was encased in the diamond so it could avoid breakdown and thereby retain all of its original water. In perhaps one of the most important mineral analyses ever made, Pearson and coworkers were able to show directly that the ringwoodite had approximately 1.5 wt % water. For the first time, here was confirmation that the mantle transition zone can be wet.

In consideration of the sum and variety of his contributions, we deservedly honor Graham Pearson for the wide interdisciplinary influence of his work in understanding the mantle at all depths.

—Steven B. Shirey, Carnegie Institution for Science, Washington, D.C.

Thank you, Steve, for your very generous and flattering words. Thanks also to those who nominated me for this award. I am rather humbled by your faith in me. I have just two things in common with Bowen: my Canadian citizenship and time spent at the Carnegie Institution of Washington. I strongly recommend both. My career has been blessed with a series of fortunate events and fruitful collaborations with a long list of talented people too numerous to mention but too important to ignore. On entering university, I wanted to be a mining geologist—something I still pretend to be when visiting diamond mines—but inspiring undergraduate teaching by Bob Thompson at Imperial College diverted my path. Having two amazing Ph.D. supervisors in Pete Nixon and Gareth Davies was key in pushing me on my way through life. Pete’s infectious fascination with the mantle and his personal integrity are something to aspire to. Postdoc mentors of the stature, quality, and generosity of Steve Shirey, Rick Carlson, Joe Boyd, and Chris Hawkesworth gave me no excuse to fail. After 15 happy years at Durham, I was lured to Canada, where I am blessed with truly supportive colleagues who make working at the University of Alberta an absolute pleasure. But I want to end by focusing on a group of people who often do not get the credit they deserve. Without the dedication, enthusiasm, and support of the lineup of lab managers and technical support I have been fortunate to work with through my career, I would have produced very little. So I’d like to acknowledge Geoff Nowell, Chris Ottley, Sarah Woodland, Yan Lou, and Chiranjeeb Sarkar, who, along with all of my students and postdocs, and my heroic wife, Sam, rightfully own some part of this award. —Graham Pearson, University of Alberta, Edmonton, Canada