Dan McKenzie (1942 - present)

With evidence for Continental Drift now accumulating rapidly, it was still proving difficult to establish what the mechanism for the plate movement was. In 1966, 51 years after Wegener clarified the problem, Dan McKenzie had just submitted his PhD on convection in the Earth’s mantle to Cambridge University when he attended a conference in New York, where he heard Fred Vine speak about sea floor spreading and magnetic anomalies.

McKenzie applied his knowledge of thermodynamics to the problem of how plates move, and came up with a model which demonstrated a far more dynamic Earth than anyone had previously thought. He suggested there are two layers in the mantle, each of which are in motion, controlling the movement and behaviour of the tectonic plates above. ‘The viscosity of the lower mantle’ was published in 1966.

McKenzie has also modelled the generation of magmas at both mid ocean ridges and mantle plumes/hot spots. He helped develop our understanding of the factors controlling the partial melting of the mantle, and how the original composition of the magma may change with time as it moves upwards, cools and mixes with other magmas at shallower levels. Following on from this work McKenzie has extended his studies to the plate tectonics of other planets, notably Venus and Mars.