Chapter 2

AGU, Spring 1967

The American Geophysical Union holds large research meetings twice a year. In 1967 McKenzie attended the Spring Meeting in Washington. At the session on Sea Floor Spreading, Jason MorganJason MorganJason Morgan (1935-present) took his PhD at Princeton where he spent most of his career. His work on plate tectonics, published 1968, focused on magnetic anomaly data, in contrast to McKenzie’s application of fault slip directions; they are fundamentally the same theory. Morgan went on to apply and refine Tuzo Wilson’s ideas about hot spots and mantle plumes, together with mantle convection. of PrincetonPrincetonThe Department of Geology at Princeton University was led in the 1930s by Dick Field, who drove forward marine geodesy with the pioneering work of Vening Meinesz, a pioneer of marine gravity surveys from the Netherlands. Under Field’s direction, Maurice Ewing and Harry Hess took part in the 1936 research voyage to the West Indies in the submarine Barracuda, establishing the existence of negative gravity anomalies along island arcs. Field was also was a powerful advocate of Ewing’s pioneering seismic experiments at sea and he showed Ewing’s seismic data to Teddy Bullard. When Bullard returned to Madingley Rise, he introduced the idea of marine seismology to the UK. From 1950, Harry Hess ran the Department and continued the global geophysics approach. He, Jason Morgan and Bob Dietz were enthusiastic advocates of plate tectonics. spoke about his work unifying ridges, trenches and plate movements – essentially the same ideas that McKenzie was working on. But McKenzie did not hear him speak. Morgan’s conference abstract was about a published paper which McKenzie had already read and had not found interesting, so he left the session before Morgan spoke. “At big meetings I have far too many things I’m interested in, so I missed his talk and it made no impact on anyone, except Xavier Le PichonXavier Le PichonXavier Le Pichon (1937-present) is a French geophysicist known for his comprehensive model of plate tectonics which divides the lithosphere into six main plates. He has been professor at the Collège de France since 1986.…I didn’t discover what was going on until later that year, after I left ScrippsScrippsScripps Institution of Oceanography, San Diego, California was established to support marine biological research, but from 1908 onwards pioneered geophysical research in the oceans. Teddy Bullard was a frequent visitor and undertook early ocean floor heat flow measurements with Roger Revelle. In 1962 the University of California established the new Institute of Geophysics and Planetary Physics alongside Scripps in La Jolla. and went to LamontLamontLamont Geological Observatory (now Lamont-Doherty Earth Observatory) was established by Columbia University, New York in 1949 following a gift of land by the Lamont family. Maurice Ewing was its first director and his dedication to exploration and discovery established it as a world leader in geophysics. Ewing demanded comprehensive data collection on Lamont research voyages, building a vast store of data: the Vema alone covered more than a million miles in her working life at Lamont. Despite this, Ewing and his colleague Walter Bucher did not accept the mobilist worldview of plate tectonics..”

READ THE PAPER — Morgan, W.J. 1968. Rises, trenches, great faults and crustal blocks. Journal of Geo-physical Research. 73, 1959-1982.


Figure describing the movement of crustal blocks around a pole, from Jason Morgan’s paper ‘Rises, Trenches, Great Faults and Crustal Blocks’ given at the 48th Annual Meeting of the America Geophysical Union (AGU) on 19 April 1967.