Tonight we are here to acknowledge Peter Kelemen, one of the leaders in our field. The N. L. Bowen Award ceremony is unusual for AGU because there is only one person who is being honored, and most of the people in the room know the person or of the person, and have been influenced by his work. The time constraints are less rigid, and the occasion is less formal. That permits Peter to let us hear a bit about where he comes from and what he has done, and for us to have the opportunity to listen to his perspectives.

We can be reasonably sure, Peter being Peter, that those perspectives will have the elements of edge, philosophy, rebelliousness, creativity, sensitivity, and humor that are hallmarks of Peter's persona, and in his citation perhaps he deserves a bit of the same. So, in honor of the relatively personal aspects of this award occasion, I thought we might risk having the well-deserved accolades mixed with a bit of affectionate roasting.

There has been one consistent characteristic of Peter's career apparent since his early papers and the first time I met him more than 15 years ago: Virtually everything in VGP and that all of us work on is pertinent to or can be explained by reactions between migrating magma and the rocks through which they must pass. I was under the impression early in Peter's career that I could take the conclusions of any one of his papers and simply cut and paste one into another because the fundamental conclusion would always be the same. In fact, for the first 6 years and dozen papers of his publishing career, every paper but one was some aspect of melt-rock reaction. Now, what would drive a person to such a persistent view of the world and to pursue it with such passion?  Peter answered this question for me in the early 1990s with a 10-page, single-spaced letter that was part scientific and part from the heart. For the dozens of you in the room who have been the recipient of Peter's paper reviews, you know that long, single-spaced missives come quite naturally to him.

So, not so long ago, but in the beginning of Kelemen time, like many young searchers, he went to India and pondered the meaning of life, in Peter's case while doing geological fieldwork. I am sure there were many components to his experiences, but the one that concerns us is the vision that hit him sitting on an outcrop of mantle peridotite in the Himalayas. There were all these rocks, tens of kilometers thick, with dikes going through them. How could the magma possibly traverse such long distances without being fundamentally modified by the materials through which they passed? And how could they then not leave a record of their passage?

Armed with this vision, Peter headed to graduate school. Since that time, he has investigated melt-rock interaction with amazing breadth and depth, through a combination of careful fieldwork, quantitative chemical modeling, and investigation of the fluid dynamic instabilities associated with migrating magma. He was able to show us that the ubiquitous "dunite channels" in exposed peridotites were the remnant tracks of migrating magma. This recognition has become a guiding principle for a wide range of subsequent developments in fields that include ophiolite field studies, the fluid dynamics of melt migration, chemical consequences of melt migration, U-series disequilibria, and the understanding of the variations in major and trace element composition of the ocean crust.

To investigate peridotites, Kelemen was also walking over the ocean crust, and he decided to turn his attention to the physical aspects of its origin by carefully looking at the structures and the chemical compositions of the gabbroic layers. This work led to papers that definitively laid to rest competing models for the physical construction of the ocean crust that had been put forward by many geologists and geophysicists over the previous decade.

Kelemen's personality is highly questioning and interactive and, therefore, at the same time all this other work was taking place, he was talking to the seismologists at Woods Hole who were carrying out active work on the structure and formation of volcanic margins during continental breakup. This interaction led to a very productive collaboration with Holbrook and the publication of a number of papers that relate the velocity results from the seismic studies to the chemical compositions of the seismically defined layers.

Amid these productive forays in other directions, melt migration was never far from his mind. The mantle wedge above subduction zones is one of the best candidates for mantle/melt interaction, as melts generated above the slab must rise through the mantle wedge to the overlying crust. Here is where continents likely are generated. Kelemen has worked steadily on multiple aspects of this problem. One of the best places to examine the continental crust is where the crust is laid on edge so that a vertical section through much of the crust can be investigated. Kelemen co-led such an investigation of the Talkeetna Arc section in southeastern Alaska to try to constrain and understand convergent margins and the formation of the continental crust.

Thinking about the continental crust inevitably leads to the question of why the continents are high SiO2 while magmas coming from the mantle largely are not. With his new training and orientation in geophysics as well as geochemistry, Peter investigated the physical aspects of delamination of continental lithosphere, and with Matthew Jull produced the seminal papers that investigate this process. They showed that crustal delamination is not only qualitatively appealing but also physically inevitable under certain conditions. The origin of the continents is one of the most exciting unsolved problems in our overall understanding of Earth structure; all future work on the problem is going to have to take account of Kelemen's contributions.

As many of you are affectionately aware, Peter also has long had a position as "enfant terrible" in our field. I remember at a major NSF planning meeting when he stood up to say to the head of OCE [NSF Division of Ocean Sciences] that he was not telling the whole truth to the community and we knew he wasn't. "Diplomatic" is not a word one often associated with Dr. Kelemen. I am sure that, like me, many of you have gotten a signature "Kelemen review" of your paper, sometimes with dozens of detailed comments that need to be dealt with, and then when you deal with them he may contest how you responded to every one. That said, Peter's substantial reviewing efforts have led to a significant increase in the quality of dozens of published papers, a major but little recognized contribution.

But those days of "enfant terrible" have appropriately passed. Peter emerged as a leader of the hard rock group at Woods Hole, recently was co-chief scientist on an ODP drilling leg, and is taking up the leadership tasks that correspond with the breadth of his scientific vision and energy.  One of the favorite things I learned in graduate school came from Gil Hanson, who said, "There are no bad problems, there are only bad scientists." I think Peter exemplifies the positive aspects of this perspective. It was not necessarily that his vision of mantle-melt interaction was prescient rather than delusional. But Peter pursued this problem with such energy, curiosity, and scientific vigor that he has in many ways redefined our field. It led him to interact across a very large range of disciplines, and to write papers in geophysics, geochemistry, fluid mechanics, seismology, and tectonics, to lead ambitious field programs, to do experiments, and to direct theses in theoretical geodynamics. Out of all these interactions has come a host of scientific advances, new problems to explore beyond melt/rock interaction, and the need for all of us when interpreting our data to consider the consequences of the inevitable reactions that take place during transport.

Friends and colleagues, please welcome Peter Kelemen, a scientist who has redefined the way we think, and one of the most productive and influential contributors to our field in the past 5 years.

---Charlie Langmuir, Harvard University, Cambridge, Mass.

Response

Thank you, Charlie, for your kind words and your support.

I am particularly grateful to be receiving the N. L. Bowen Award. As a graduate student, I imagined that I was engaged in a scientific discussion with Norman Bowen. This was problematic, since Bowen died the year I was born. But I persisted, in part by studying other scientists' discussions with Bowen, and I wrote a term paper on his long dispute with Daly and Fenner on assimilation, which I added as an appendix to my dissertation.  In those days, I thought it would be the pinnacle of success to be associated with Bowen by receiving this award. I imagined that if this happened, I would then announce that I was quitting geological research to do something entirely different. Unfortunately, I have grown so old and forgotten so much, I no longer remember what it was I intended to do.

Instead, I decided to give the customary speech thanking everyone who has worked with me. This is partly a defensive strategy: Ken Kesey described the telescopic rifle sight, the cross-hairs that are inscribed in every spotlight. I know, a lot of you are asking, "Why him"? It's a good question, I agree, so I thought the least I could do is share the blame.

I have a habit of seeking out father figures and mentors. Certainly, Norman Bowen is one of these father figures for me. I've decided to focus on them here, and so mothers get short shrift in this presentation. To try to offset this, right at the outset, I want to say that I certainly would not be here without the support of my wife, Rachel Cox. Rachel, together with my mother and stepmother, deserves most of the credit, and none of the blame.

But now back to fathers. I have an excellent father, and in fact he is here tonight. As a refugee from both the Hungarian Nazis and the Hungarian Communists, but a lover of Central European culture, my father taught me by example never to join any political groups, but always to appreciate what the world has to offer. My Dad is also very well educated, reading six or seven languages. He remembers more math than I ever learned, and studied physics and chemistry at Princeton soon after World War II with Einstein and Von Neumann. After Scott Lehman met Dad, he said, "What a surprise; I would never have guessed that your father would be such a sophisticated person."

Though he seems genteel, the other thing to know is that my Dad is tough. When things don't look so great, my father says something like, "Well, I am just glad we're not living in the Congo," meaning, I guess, "Well, this is a lot better than Budapest in 1943." Anyway, having had such a good father, I set out in search of more.

I didn't think I could live up to my father's legacy, so I decided to study literature and philosophy, but I was really impressed with the geology faculty at Dartmouth, so I switched majors toward the end of my junior year. It was hard catching up to all the real geology majors, and anyway I have always been somewhat slow on the uptake. At Dartmouth they had a postgraduate fellowship for foreign study, but it couldn't be used for grad school. My friend Mark Sonnenfeld and I jointly applied for one, split the $6000, and in 1980 went to India to map in the northwest Himalaya.

Two things happened that year that gave my life its subsequent direction. First, in the Himalaya I saw felsic dikes cutting mantle peridotite, and abundant peridotite inclusions in the granitic Ladakh batholith. The felsic/ultramafic contacts had extensive reaction zones. I was inspired, awestruck, dizzy with the vision of how intermediate composition igneous rocks---and continental crust---could form by reaction between felsic magmas and ultramafic rocks.

I imagined that this idea would solve the "andesite problem." As I said earlier, I was a little out of touch, having done my major in a year and a half, and being intrinsically a bit slow, so I didn't realize that there no longer was an "andesite problem," or at least, if there still was an andesite problem, it was that there were too many solutions. No one wanted another idea. But I had one, and I didn't know it.

Anyway, I wanted to work on peridotite, and I wanted to go back to the Himalaya. I knew Bernard Evans was the expert on peridotite metamorphism, and Peter Misch was a Himalayan geologist, so I applied to the University of Washington. I only applied to that one place. I didn't know that most academic careers in U.S. Earth science begin at Harvard, MIT, Columbia, Princeton, Yale, Berkeley, and Caltech---out of touch, once again. I had a B+ average from college, and I hadn't taken the GREs---didn't believe in them---but Bernard pulled my file out of the discard stack at the last minute.

I didn't deserve my luck, but UW was the perfect place for me. I found a whole stack of father figures, not just Bernard Evans and Peter Misch, but also Mark Ghiorso, Stu McCallum, Nik Christensen, Darrel Cowen, Tony Irving, Ed Mathez, John Delaney. There is no way I could have done open system calculations without Mark Ghiorso, no way I would have known what to do with Mark's melt model without the phase diagram legacy imparted by Stu McCallum, no way I would have had a clue in later years at Woods Hole without Nik Christensen's classes on oceanic crust. Meanwhile, Bernard didn't really believe in wild speculation about open systems, and held my feet to the fire.

Another thing that was lucky for me was that UW wasn't completely in the mainstream. I could develop my "andesite inspiration," modeling reactive melt transport in the mantle, without having to immediately confront other hypotheses about andesites that were current at MIT and Berkeley, or about mantle "chromatography" that were just being developed at Caltech, Paris, and Montpellier. When I did emerge into the "real world," I had something of my own that was almost ready.

The second important thing that happened to me in 1980 was that, with some climbing friends who were geologists trained at Middlebury, I formed Dihedral Exploration, a consulting company specializing in "extreme terrain mineral exploration." One of my business partners was Geoff Radford, with whom I worked every summer from 1981 through 1991.  Geoff died in an avalanche in 1992, but I still think about him just about every day. It seems that ore deposits are almost always in places with terrible climbing: bad rock, unstable snow, and lousy weather. It was scary work. But Geoff would say, "Who says life is supposed to be fun?" He lived simply to do every job right. If I complained about being away from home (or grad school) too long, he'd reply, "Think of soldiers in WWII, or whalers in the nineteenth century, gone 3 or 4 years at a time." Some wayward boys have to grow up in the Army. I had Geoff Radford and Dihedral Exploration.

Okay, so this is going on too long. Rather than singling people out for blame, I am going to blame them in clumps. Since I've been talking about Geoff Radford, the first clump is the tough clump. In thinking about this talk, I found that Peter Molnar and Dan McKenzie kept coming to mind. They haven't been formal mentors of mine; maybe it is just hero worship. Plus my ion probe mentor at Woods Hole, Nobu Shimizu, belongs in this group; most of you probably think Nobu is pretty warm and fuzzy, but he really isn't. And Charlie Langmuir probably fits best in this group, along with Adolphe Nicolas, who provided a shining example of how to use field geology to constrain geodynamics but never liked my work very much. Among the younger cohorts, my colleague Brad Hacker seems to fit in here. I really count on them to be honest, and they are. Just as an example, last year Dan McKenzie and I were talking, and I said something about how most scientists have some bad habit that prevents them from living up to their potential. And Dan said, "Oh, not you! You're not that smart, and you had a terrible education. You're an overachiever!"

In contrast, another category is the supportive clump, and foremost among them is Stan Hart. Not only is Stan an exemplary scientist in many ways, but he is also actively, consciously, constantly supportive of younger scientists. No one spends more time advising grad students, postdocs, and junior colleagues. No one spends more time nominating people for awards, and inducing others to follow his example. I would also single out Mike Purdy in this context. Due in part to Mike's matchmaking at WHOI, I started working with Steve Holbrook. I am not sure if Steve belongs in the tough clump or the supportive category, but he dragged me into seismology, and he certainly deserves to share the blame for my Bowen Award.

Also in the supportive clump are Jack Whitehead, Marc Parmentier, Marc Spiegelman, Einat Aharonov, Jun Korenaga, Mike Braun, and Matthew Jull---all geophysicists who tolerantly helped me with my naive attempts to contribute something to geodynamics---geochemist Ken Sims who manages to overlook the fact that I still don't know what a U-series activity ratio really is, and similarly Gene Yogodzinski, who tries not to emphasize that I have never actually been to the Aleutians. There are many more of you here. Thank you, Tony Morse.

Henry Dick should be mentioned here. Without a doubt, he is certainly to blame. It's just so hard to know how to categorize Henry. Tough? Supportive? Fratricidal? We are all siblings in Henry's dysfunctional family. Anyway, I learned a tremendous amount from Henry, about science and about survival. I've benefitted enormously from his visionary geodynamics seminar at WHOI, and we all benefit from his fierce efforts on behalf of drilling oceanic lower crust.

Last but not least, I have to thank (and blame) Greg Hirth, who has become my advisor in a second round of graduate school, patiently teaching me about mineral physics. I hope I have taught him something or other in return. Anyway, we've done the best of science together, building the Giant Tripod and deploying BOLO, the Blimp for Onland Oceanography. One great thing about Greg is that he's not intimidating and he's not intimidated. He has quite a famous father, and Greg has followed directly in his father's footsteps, but he never seemed to feel as though he was in a shadow. In fact, I think this sense of fearless (foolish?) confidence describes most of the people on this list.

That's important. There is a risk that we can feel diminished by comparison with figures like Norman Bowen. It can seem that they lived in a lost golden age. Geoscience is full of these. Not only were we absent when Bowen, Holmes, and Daly brought physical chemistry to geology, and thus invented petrology, but we were also babes at the dawn of plate tectonics, when Lamont, Princeton, Scripps, and Cambridge were inhabited exclusively by visionary geniuses, and we missed the birth of geophysical fluid dynamics. Even more recently, we were on the sidelines---protomammals, cowering in the bushes---when marine seismologists were giant dinosaurs. They stomped, and the Earth shook. What can we possibly do that could measure up to this past greatness? These are thoughts that haunt you when you get the Bowen Award, realizing that your contribution seems very small in comparison with Bowen's. This is what Yale poetry critic Harold Bloom calls "the anxiety of influence," and it leads to books like the recent one entitled The End of Science.

Surely, that's not what people have in mind when they set up such awards. Instead, they hope that we will be inspired to greater things by a reminder of Bowen's work. For example, I thought of ending this presentation with the idea that receiving the Bowen Award may be a signal that it is now time for me to grow up, to act more like a father and less like an inquisitive child. I am sure that my students would appreciate this.

But I am not ready for that yet. I've often been tempted to entitle presentations at AGU, "Fools Rush in Where Angels Fear to Tread." It can seem inappropriate to emphasize ignorance in this way, like George W. Bush touting his poor academic record at Yale as some kind of perverse, reverse credential. And yet, there is some virtue in exploring new worlds, even if they are thickly inhabited, and are new only to us. Today I presented work on earthquakes, which I've been doing with Greg Hirth. Neither of us is burdened with an extensive knowledge of current work on this topic, or the history of the field. We do know that there are many more smart people working on earthquakes than there are igneous petrologists and mineral physicists added together. But the field is new to us, and as a result, with a little luck, perhaps we will come upon something that is new to them!

I have one more thought to share about fatherhood. When Henry Dick was elected an AGU Fellow, I was delighted for many reasons. One is that the award helped him see that he doesn't have to try so hard to defend his legacy. If you find yourself in a talk or looking at a poster thinking, "I already said this, they should give me more credit!," stand back. You probably didn't say it quite that way, and what seems like a small difference now could be the beginning of a great new direction. Again I'd like to quote Dan McKenzie, who told me that the work that makes him proudest is the work for which he is no longer cited, that has passed into the mainstream and lost its identification with him. Few of us will have the impact that Dan has, but I am sure that you've all sent some ideas into the mainstream here at this meeting. They are your adult children. Let them live their own lives.

Well, long before this point in the presentation, Geoff Radford would have said, "Shut up and get back to work, Peter." Thanks again, Charlie, for your kind words, and thank you all for your attention and your patience.

---Peter Kelemen, Woods Hole Oceanographic Institution, Mass.