John W. Hernlund received the 2010 Jason Morgan Early Career Award at the 2010 AGU Fall Meeting, held 13–17 December in San Francisco, Calif. The award is “for significant early-career contributions to tectonophysics.”
The Tectonophysics section is delighted to present the second Jason Morgan Early Career Award to John Hernlund for his seminal contributions to mantle dynamics and the promise of much more to come. Hernlund, a geodynamicist, has a remarkable ability for cross-disciplinary thinking that links geodynamics, seismology, and mineral and rock physics—the essence of tectonophysics, which incorporates all of these disciplines. Shortly after discovery of the postperovskite phase of (Mg,Fe)SiO3 in 2004, Hernlund produced a model inNature proposing a double crossing of the phase boundary between the perovskite and postperovskite phases as an explanation of several perplexing aspects of the lowermost layer of Earth’s mantle, the so-called D” layer. Such a model, coupled with detailed understanding of this phase change and the effect of chemical composition on it, especially the effects of aluminum (Al) and the spin states of iron (Fe), is fueling and will continue to fuel discussion and models about early Earth, the temperature of the core, the heat flow across the core-mantle boundary, the significance of discontinuous zones of ultralow seismic velocities (ultralow-velocity zones, or ULVZs), and more. One such advance already accomplished by Hernlund and coworkers is a model, also published in Nature, postulating a dense basal magma ocean that they envision developed in very early times, cumulates from which may explain the ULVZs. The seeds of much of this work can be seen in Hernlund’s earlier work at the top of the mantle on melting instabilities induced by lithospheric extension when he was still a student at University of California, Los Angeles with Paul Tackley. His ideas have now flowered with these applications to the bottom of the mantle in the early years of his independent career—Harry W. Green, University of California, Riverside
I am honored to receive this award, and I am happy that I can still be considered an “early-career” scientist. For me, this award represents an encouraging vote of confidence from colleagues whom I respect and admire and sets a high standard of expectations for my future. It is also a pleasure to see the breadth of disciplines that are already recognized by this award. It sets a precedent that reflects the broad spectrum of science that finds shelter under the umbrella of tectonophysics.
The award description states that it is granted “for significant early career contributions to tectonophysics.” However, the groundwork for everything I have done was laid long ago by the efforts of my senior colleagues, and I am grateful for their hard work in preparing the way for the next generation of scientists. I also have countless colleagues and mentors (too many to list in this small space) who have shaped my development as a scientist and played vital roles in much of my research. My work is also closely tied to that of my colleagues in many different disciplines. Without the discovery of postperovskite, or the observation of multiple seismic discontinuities in the deepest mantle, there would be no postperovskite double crossing. If there were no detections of ULVZs, or experimental evidence of dense melting in the lowermost mantle, there would be no basal magma ocean. Therefore, this award honors the achievements of researchers who are working in a broad variety of fields and highlights the remarkable synergy by which we are able to address these challenging scientific problems together as a community. We are greater than the sum of our parts.—John W. Hernlund, University of California, Berkeley