It is a great honor for me to have the opportunity to deliver this citation for Marcia K. McNutt, the 2007 recipient of AGU's Maurice Ewing Medal. Marcia has made a significant contribution to our understanding of the structure of oceanic lithosphere, served in leadership roles in the marine scientific community, and instigated new directions and technologies for ocean exploration.
Marcia received her undergraduate degree in physics and studied for the Ph.D. with Bob Parker and the late Bill Menard at the Scripps Institution of Oceanography. Her thesis led to two seminal papers on oceanic and continental isostasy. The first showed that flexure due to a young volcanic load could influence the subsidence and uplift history of nearby, preexisting volcanoes. This hypothesis, which explains why some seamounts and oceanic islands show uplift rather than subsidence, has had wide implications for basin development and sea level change. The second used 3-D spectral methods of analyzing topography and gravity data to argue that the Australian lithosphere responds to loads as a relatively strong structure at short time scales and a weak one at long geological times. This method is now widely used and is at the center of current debates concerning the rheology and strength of continental lithosphere.