Distinguished Australian geologist who made profound contributions to the origin of granites.
Bruce Chappell’s research began just as the magmatic/partial melt origin of granite was being accepted, ending ‘the great granite controversy’. He since dominated and largely determined the global directions of research on granites as igneous rocks, quickly recognising that many granite magmas move bodily away from their sources deep in the crust as a mixture of melt and solid residues.
Fourth of five children, he lived in Arding, south of Armidale, where his father was primary school teacher and his mother Eva ran the post office and telephone exchange. Intellectually outstanding, he gained first-class honours and a University Medal in 1959, and an MSc in 1961. In 1960 he was appointed lecturer in Geology at ANU where he was awarded a PhD (1967) and DSc (1990). He became a Fellow of the Australian Academy of Sciences in 1988.
Much of his work was done with the late Alan White. In their long-term, brilliant work on the granite suite, Chappell and White became intellectual successors to H H Read and W S Pitcher. Meticulous mapping of plutons, careful microscopy, and huge banks of laboratory geochemical data were the hallmarks of his work. In 1974, Chappell and White recognised the fundamental concept of I-type and S-type granites, showing how both types come from partial melting of continental crust, (the ‘restite model’), and that I-type granites could not be mantle-derived. This remains the only fundamentally new process dealing with the evolution of igneous rock suites since Bowen’s reaction series (1928).
Chappell showed that much of the petrographic variation of the ‘granite clan’ results from fractionation, which can occur on a crustal scale. With others, Chappell and White accounted for the great variation in emplacement temperature of granites by zircon saturation. Most of Chappell’s work was done in the Lachlan and New England Belts (eastern Australia), a massive ‘sea’ of granite; but he also worked in California, Cornwall, and Scotland. His study of Cornish granites was one of the most significant studies of a British igneous province in the last 80 years, and resolved the problem of the ‘tin granites’ (showing their source rocks were not abnormally high in tin).
Chappell pioneered X-ray spectrometry for trace element analysis and designed and built the first automated sample-changer. This led to significant contributions in several fields, most notably lunar samples, for which he was the Apollo Program’s most productive analyst. Chappell’s master data set on the Tasmanide granite suite, a lifetime achievement, is to be released in three mammoth sets. His work, with Alan White’s, on the upper half of the Streckeisen diagram will form the basis of all future studies of the granite clan.
Chappell gave generously of time and money to young geologists. A rough diamond, he was a gentleman, who hated suffering; a wonderfully argumentative, maddening, intellectual companion, deeply loved by his many friends.
Bruce Chappell, born Armidale NSW 20 November 1936; died Canberra 22 April 2012.
Written by: John Dewey
A longer version of the above obituary by Professor Dewey
Bruce Chappell was one of the most distinguished Australian geologists of his generation whose contributions to the origin of granites are profound and clever. His principal scientific interest was the origin of granites; the beginning of his research coincided with a broad acceptance of their magmatic/partial melt origin on the publication, in 1958, of Tuttle and Bowen’s classic research, which ended “the great granite controversy” of whether granites are metamorphic or igneous rocks. He has since dominated and largely determined the global directions of research on granites as igneous rocks. He quickly recognized that many granite magmas move bodily away from their sources deep in the crust as a mixture of melt and solid residual material and the proportions of these components determine the composition of such granites, and related volcanic rocks. This restite model is the only fundamentally new process dealing with the evolution of igneous rock suites since Bowen’s book on the reaction series in 1928. Bruce’s principal hero was Eskola. who was best known for his work on metamorphic facies but whose influence emerged in Bruce’s recognition of the very close relationship between bulk chemical composition and mineralogy of granites, and that such a relationship could be precisely quantified. While this relationship is now generally recognized, it was not known in the mid-1960’s, and was a critical step toward the recognitions of I- and S-type granites.
Bruce was born in Armidale NSW on November 20, 1936 and died in Canberra on April 22, 2012. The fourth of five children, he lived in Arding, some sixteen kilometres south of Armidale, where his father John was the sole primary school teacher and his mother Eva ran the post office and telephone exchange. A physically tough boy, he cycled to and from Armidale to high school and, later, the University of New South Wales. He was outstanding in mathematics and physics but, fortunately, was persuaded, by Allen Voisey, to read geology. Intellectually outstanding, he gained first-class honours and a prestigious University Medal in 1959, and an M. Sc. in 1961. His Honours mapping was of a 500 square kilometre area in New England NSW, where his interests in granite and the geochemistry of grewackes were founded. In 1960, he was appointed lecturer in Geology at the ANU where he was awarded a Ph. D in 1967 and D. Sc. in 1990. The recipient of many awards, medals, and honours throughout his career, he became a Fellow of the Australian Academy of Sciences in 1988.
Much of his work was done with the late Alan White, Chappell’s life-long geological research associate. In their long-term, brilliant work on the “granite” suite, Chappell and White became the intellectual successors to H. H. Read and W. S. Pitcher. Chappell’s work was characterized by meticulous field mapping of plutons, especially his field petrographic mapping, his careful microscopy, and his huge amount of laboratory geochemical data, mostly generated by his own hands. Chappell and White recognized, in 1974, the fundamental concept of I-type (clean low-alumina with few or no inclusions, and S-type (garnet/cordierite-bearing high-alumina with pelitic and greywacke inclusions) granites. They showed that all both types come from partial melting of the continental crust, the restite model, and image their source material, and that I-type granites cannot be mantle-derived. At about the same time, Ishihara published his brilliant work on ilmenite versus magnetite granites showing that this reduced versus oxidized classification coincides with S and I-type granites. This was of great practical importance in determining the likely style of economic mineral deposits. Chappell showed that much of the petrographic variation of the upper half of the “granite clan” results from fractionation; Chappell and Hine (2006) showed that fractionation can occur on a crustal scale. With Ian Williams, Doone and Leslie Wyborn, Chappell and
White accounted for the great variation in emplacement temperature of granites from low-temperature S-types up to 1000°C for cpx-bearing I-types by zircon saturation. Most of Chappell’s work was in the Lachlan and New England Belts of eastern Australia, a massive “sea” of granite but he also worked in California, Cornwall, and Scotland. His study of the Cornish granites is one of the most significant studies made of a British igneous province, in the last eighty years, and also resolved the long-standing problem of the “tin granites”, showing that the source rocks were not abnormally high in tin. He was utterly rigorous in his science and worked intensely for long periods. He was not only an original and clever thinker but a master of instrument development. He pioneered the use of X‑ray spectrometry for trace element analysis of rocks and designed and built the first automated sample changer. This led to significant contributions in several other fields, most notably the lunar samples, for which he was the most productive analyst during the Apollo Program. Chappell was the doyen of granite studies world-wide; he was a brilliant petrographer in the mould of Stuart Agrell. Chappell’s master data set on the Tasmanide granite suite, a truly prodigious lifetime achievement, is to be released in three mammoth sets. His work with that of Alan White on the upper half of the Streckeisen diagram will form the basis of all future studies of the granite clan.
Bruce had four great loves, sport (Aussie rules, cricket and golf), granites, music and family and friends. He adored the music of Mozart, enjoyed sport, and loved his family but was utterly single-minded about granites. He was also extremely fond of sausages and lamb chops. He had a prodigious memory; he knew all the intricate details of the periodic table, was a walking cricket encyclopodia I had the good fortune to spend a month with him in his house in the Canberra suburb of Yarralumla in the November before his death. His health was deteriorating very fast but was eager to discuss the origin, ascent, and emplacement of granites; in that short time, I learned a huge amount from him. He could be irascible, spiky, dismissive, and judgmental with those who disagreed with his geological or left-wing republican political opinions and staunch support of the Australian Republic but this was because he had well-thought–out positions firmly and honestly held. He, genuinely, could not understand why others failed to agree with him. He was a genuine socialist who believed in sharing at all levels of society and nations. He practiced what he preached in giving his time and money to promising young geologists He was a rough diamond, a very kind, generous, and moral man, a gentleman who hated the suffering of people and other animals, and a wonderfully argumentative, maddening, intellectual companion who was deeply loved by the many who became his friends.
John Dewey
Key publications.
Chappell, B. W., and White, A. J. R., 2001. Two contrasting granite types: 25 years later: Australian Journal of Earth Sciences, 48, 489-499.
Chappell, B. W., and Hine, R., 2006. The Cornubian Batholith: an example of magmatic fractionation on a crustal scale: Resource Geology, 36, 203-244.
Chappell, B. W., White, A. J. R., and Hine, R., 1988. Granite provinces and basement terranes in the Lachlan Fold Belt, southeastern Australia: Australian Journal of Earth Sciences, 35, 505-521.
Chappell, B. W., White, A. J. R., Williams, I. S., Wyborn, D., and Wyborn, L. A. I., 2000. Lachlan Fold Belt granites revisited: high- and low-temperature granites and their implications: Australian Journal of Earth Sciences, 47, 123-138.
Chappell, B. W., 2004. Towards a unified model for granite genesis: Royal Society of Edinburgh Transactions, 95, 1-10.