Stuart Ross Taylor

2002 Walter H. Bucher Medal Winner

Australian National University

Stuart Ross Taylor was awarded the 2002 Bucher Medal at the AGU Fall Meeting Honors Ceremony, which was held on 8 December 2002, in San Francisco, California. The medal is given for original contributions to the basic knowledge of the Earth’s crust and lithosphere.


“I don’t quite remember when I first met Ross Taylor, but it was a long time ago, and I am almost certain it was in a noisy pub over some beers. I was a young and eager beaver then, and Ross was the elder statesman geochemist. Ross always mumbled a little, and I did not understand most of the things he said. But I liked him a lot. It seemed that, unlike most geochemists, he was a genuinely nice guy. Well, I am no longer all that young, but to me, Ross is still the quintessential elder statesman, a man of encyclopedic knowledge and deep understanding of geochemistry and of our planet and its neighbors. Ross has been around for more than three-quarters of a century, and I am confident he is planning to be around for at least another quarter. I am deeply honored that he has asked me to read this citation.

“Ross was born and raised in New Zealand, and he received his bachelor’s and master’s degrees at the University of New Zealand. After that, he became a world traveler, spending virtually his entire adult life abroad. His travels took him to the United States, where he received his Ph.D. degree under the supervision of Brian Mason. That was not enough; he went on to earn a Master of Arts, while working as a ‘demonstrator’ at Oxford. From there, he went on to become Senior Lecturer in Geochemistry at the University of Capetown, and he finally settled down, more or less, at the Australian National University as Professorial Fellow until he retired to become Emeritus Professor.

“Ross is looking back, and forward, at an un-finished career of enormous scientific breadth and scholarship as well as truly fundamental contributions. His scientific opus is astounding and humbling. He has published about 230 papers on the subjects of lunar geochemistry, meteorites, cosmochemistry, trace elements in volcanic and sedimentary rocks and minerals, analytical methods, and about continental composition and evolution. On the side, he has written nine books on subjects like solar system evolution, the Moon, and most important today, The Continental Crust: Its Composition and Evolution.

“Ross has received many awards, including the Norman Bowen Award by the AGU in 1988, the Goldschmidt Medal of the Geochemical Society in 1993, the Gilbert Award in planetology by the Geological Society of America in 1994, and the Leonard Medal of the Meteoritical Society in 1998. Today, he receives the Walter Bucher Medal ‘for original contributions to the basic knowledge of Earth’s crust.’ On this subject, he has not just been a pioneer. He is the pioneer. Thirty-five years ago, Ross wrote a classic paper on ‘the origin and growth of continents,’ and this was just the first of 30 papers on the subject. He developed the ‘andesite model’ of the continental crust, which derives the crust by accretion of arc volcanic rocks. He refined this model by taking special account of Archaean rocks, which he showed differ systematically in their geochemistry from younger rocks. He concluded that about 75% of the present-day crust was in place 2.5 billion years ago.

“Why should anyone care about the chemical composition of the continental crust? Well, it turns out that this composition matters to almost everything else. Ross realized that 30 to 50% of the Earth’s total budget of highly incompatible elements, including all the heat-producing elements, reside in the crust. This has enormous ramifications for understanding the Earth and its evolution as a whole. The machinery that distilled these elements with such efficiency into a thin layer of scum floating on top of the mantle is still not fully understood. A few years ago, most geochemists were happy with the notion that the depleted complement of the continental crust is confined to the upper third of the mantle. But now, the witch doctors practicing seismic tomography tell us that subduction continues all the way into the lower mantle. What goes down must come up, and therefore the Earth cannot maintain a neatly layered mantle. Thus, knowing exactly what’s on top is crucial to knowing what’s still down there and what isn’t. So the composition of the crust is crucial to any full understanding of the Earth’s mantle and its evolution. Ross summarized these relationships with an ingenious and utterly simple diagram that relates ionic radius and valency of any lithophile element to the degree of enrichment in the crust. This diagram is a direct descendant from the principles of geochemical substitution laid down by Goldschmidt two scientific generations earlier. Perhaps this is not surprising, considering there is also a line of descent from Victor Goldschmidt via Brian Mason to Ross Taylor. Ross is not resting on his laurels. His most recent paper on the composition of the Earth’s crust was published last year.

“As emeritus professor, Ross has reverted to his favorite occupation, namely, that of a ‘demonstrator.’ He is the human demonstration of the Heisenberg uncertainty principle: at any given time, and if you are lucky, you might encounter him on some university campus or at some pub. Then you know where he is at the moment, but not necessarily where he is going next, but it seems unlikely that he will ever stop working on and writing about the continental crust. It is a great pleasure to honor Ross Taylor’s seminal and continued contributions to the basic knowledge of Earth’s crust, and to present him for the Walter Bucher Medal of the AGU.”

—ALBRECHT W. HOFFMANN, Max Planck Institut für Chemie


“Thank you, Al. When I grew up in New Zealand, on a farm, there were so few people around that I never had to raise my voice, except to call to my sheepdog, so it became a habit.

“Well, it is a great honor to receive the Bucher Medal, coming as it does from such a distinguished academic society and commemorating Walter H. Bucher. I thank the society for this distinguished award.

“I owe much to my parents, who encouraged me and who made sure that I received a good education. My wife, Noël, has been a constant support in my work. Without her backup on the home front, I wouldn’t have been able to travel so much.

“But of course, such awards do not arise from one individual’s work. The message is to always have good colleagues. I was fortunate to encounter Scott McLennan at an early stage of my studies on the crust. Now we have just finished our 40th joint paper with never a cross word. Roberta Rudnick also has made substantial contributions in lots of ways.

“As a graduate student in Indiana, where Brian Mason then was, I proofread the first edition of Brian’s famous book, Principles of Geochemistry. There, I learned that Goldschmidt had worked out a crustal composition by analysing sediments from glacial lakes. So I realised that the solution to finding the composition of the crust was to let nature grind up the rocks for you, rather than trying to collect tens of thousands of samples. The crustal history is all there in the sedimentary rocks if only you can read it.

“It was Harold Urey who got me interested in the Moon, the other planets, and the great debate over whether tektites came from the Earth or the Moon. He gave me the useful advice to work always on important problems and not to admit that you are wrong too soon.

“So all this gave me a broader perspective. There doesn’t seem to be anything like our useful continental crust, which is the product of plate tectonics, elsewhere in the solar system. Given the many chance events that have resulted in forming the crust on this planet, I wonder just how unique our crust is in the universe. This has particular significance, as such crusts are probably a necessary feature for any planet that intelligent creatures or little green men could live on.

“In conclusion, I would like to pay a special tribute to the hospitality, openness, and goodwill of this great country. It is here that I have made much of my career, particularly in lunar and planetary sciences. Although I come originally from New Zealand and now from Australia, I have always been made entirely welcome in this country where I have always felt very much at home. It is in such free secular societies that science is able to flourish so well, with great benefit for everyone.”

—STUART ROSS TAYLOR, Australian National University