Drum MatthewsDrum Matthews (1931–1997) was a fellow of Kings College Cambridge when McKenzie was an undergraduate. He was young and involved in College life. Drum was originally a geologist, with a PhD on the petrology of seafloor rocks. He worked extensively at sea, collecting gravity, magnetic and depth data, plus some seabed cores and samples, including on the International Indian Ocean Experiment in 1961-63. He, with Maurice Hill, influenced McKenzie to go into geophysics as a graduate student. Matthews continued in marine geophysics, and was the driving force behind the British Institutes Reflection Profiling Syndicate which obtained the first deep seismic profiles around the UK. and Maurice HillBorn into an academic family, Maurice Hill (1919-1966) joined the Department of Geodesy and Geophysics as a research student in 1946, after war service largely in mine-sweeping, where he had worked with Teddy Bullard. He was a Fellow of Kings College Cambridge and the undergraduate McKenzie’s Director of Studies. Hill ran the marine group at Cambridge, and was a practical instrument designer; devising methods for deep water seismic surveying and measuring seafloor magnetism. Beset by illness and alcoholism, he shot himself in 1966, aged 47. were both Fellows of Kings College and saw McKenzie’s potential as a strong theoretical physicist and mathematician. They wanted him in the Department of Geodesy and Geophysics at Madingley RiseMadingley Rise, a generous late Victorian house in north Cambridge, played a central role in the development of geophysics at the University of Cambridge. It was built in 1891 for a professor of astronomy, Hugh Frank Newall, who introduced geodesy teaching at Cambridge. In 1955, it became home to the Department of Geodesy and Geophysics; Newall’s study became the Head of Department’s office. The pleasant surroundings, away from the centre of Cambridge, fostered a lively and productive community at this, the smallest of the five major world geophysical laboratories of the 1960s. In 1980, Madingley Rise became the Bullard Laboratory, and part of the newly-formed Department of Earth Sciences. , Cambridge. “They both said we don’t want to supervise you, but Teddy BullardMcKenzie’s PhD supervisor, Edward Crisp Bullard (1907 – 1980), was a noted experimental physicist who devised innovative equipment and developed a dynamo theory to model the origin of the Earth’s magnetic field. He was a student of Ernest Rutherford and a pioneer of marine geophysics in the UK. He was head of the Department of Geodesy and Geophysics at Cambridge through the 1960s, noted as a good leader who supported his staff, always managing to find a little money to get a student to a significant conference or to kick-start a new project. is your man,” he recalled. Bullard became his supervisor and set him to work on the physics of the lower mantlethe properties of the part of the mantle that lies below a depth of about 650km, which consists mainly of magnesium and iron-bearing silicates.. “He left me very much to my own devices and that suited me very well.” McKenzie shared an office with fellow graduate students Bob Parker Bob Parker (1942-present) joined Madingley Rise as a PhD student in 1963, alongside McKenzie; they shared an office and had the same supervisor, Teddy Bullard. Parker was working on the propagation of the electromagnetic field from the ionosphere into the Earth, which demanded an understanding of the oceans. Parker went to IGPP Scripps for post-doctoral research and there he and McKenzie worked out the paving stone model of rigid plates rotating on a sphere about axes. Parker had produced a flexible computer programme to draw maps and he helped McKenzie incorporate earthquake first motions around the edges of the plates as instantaneous velocity vectors, a crucial step in the arguments of McKenzie and Parker 1967. and John SclaterJohn Sclater (1940-present) was a PhD student at Madingley Rise from 1962 and shared a room with McKenzie and Bob Parker. He started work with Maurice Hill, measuring the heat flow through the ocean floor, work which he continued at Scripps where he moved as a post-doc. Teddy Bullard had been a frequent visitor to Scripps from the 1950s onwards and had designed the heat flow detector in use there. The complexity of early readings of ocean heat flow were resolved by Harry Hess’s concept of seafloor spreading; later work by Sclater supported thermal modelling of ridge spreading processes, ocean floor subsidence and the cooling of the new crust. Sclater and McKenzie worked together on the Indian Ocean in 1968.. Fred VineFred Vine (1939-present) started as a graduate student at Madingley Rise in 1962. He worked with Drum Matthews on the magnetic fluctuations recorded in the rocks of the Indian Ocean floor. Fred Vine modelled the linear patterns of normal and reversed magnetism, parallel to the mid ocean ridge and with mirror symmetry across it. They combined Harry Hess’s suggestion of sea floor spreading like a conveyor belt with the newly-discovered sequence of past reversals of the Earth’s magnetic field to produce a simple model of crustal formation at mid ocean ridges. Vine and Matthews published their model – independently discovered by Lawrence Morley at about the same time – in 1963. had started his PhD the year before, in 1962.