1980 DAN MacKENZIE
Dr. Dan Peter MacKenzie's primary contribution in marine goescience is developing theoretical models to explain the phenomenon of continental drift. This Award recognizes his broad range of contributions, their fundamental importance, and the originality of his work. Dr. MacKenzie has postulated that the continental masses are moved along by convection currents inside the earth. The area where these convection currents exhibit strongest influence is near the mid-oceanic ridges, therefore he has paid special attention to the mechanism of mountain building on ocean floors. In 1967, together with R.L. Parker, he analyzed the orientation of slip victors of earthquakes at the margins of the North Pacific and showed that the vast Pacific plate is rotating as a rigid body. Further work led to the theoretical framework for unraveling the geology of such complex regions as California. Dr. McKenzie has worked in the Pacific, Mediterranean, Indian and Atlantic Oceans _ both participating in oceanic expeditions and in theoretical studies. His field work in the Indian Ocean led to a notable study of the complicated history of that area, including the migration of the Indian continent. More recently he has generated new studies and new thought in a series of papers that relate gravity, bathymetry, heat flow and convection. The subsidence of a cooling lithosphere has important consequences for the early history of the opening of the South Atlantic. The uplift over rising mantle plumes accounts for the elevation of Iceland and the Azores.