Dan McKenzie (1942-), geophysicist, is regarded as one of the co-discoverers of plate tectonics, a concept he articulated in a joint paper with Bob Parker published in Nature in 1967. He spent the majority of his academic career at the University of Cambridge in the Department of Geodesy and Geophysics, later part of the Department of Earth Sciences. Here he workedon mantle convection and sedimentary basins, applying physical and mathematical techniques to geological problems. Since his election to the Royal Society in 1976 he has accumulated numerous honours and awards including the Copley Medal which was awarded in 2011 ‘for his seminal contributions to the understanding of geological and geophysical phenomena including tectonic plates’. Since his retirement he has continued to carry out research including work on the tectonic evolution of Venus and Mars.