Geoscience Reference
In-Depth Information
Here Be Dragons
In1965,ayoungPrinceton postdoctoral student named W.Jason Morgan(b.1935)
shared an office with the geologist Fred Vine (b. 1939), newly arrived from Cam-
bridge University. Morgan had been poring over photographs of the Moon, see-
ing what he could deduce from the heights of the walls and central peaks of lun-
ar craters. Vine's interests were more down to Earth: the geophysics of the sea-
floor. His enthusiasm proved contagious, and before long officemate Morgan had
switched his interest from the faraway Moon to the inaccessible deepsea trenches.
Morgan began to explore Holmes's idea that a pair of descending convection cells
might drag down the crust and create the great deeps. In the winter of 1966-1967,
he submitted an abstract for a talk at the April 1967 meeting of the American Geo-
physical Union titled “Convection in a Viscous Mantle and Trenches.” But when
he rose to speak, Morgan announced that he would talk on a different topic. A
few months of work had led him to a startling new theory. But the audience had
come to hear about deep-sea trenches. Those who might have had an interest in
his new topic had not known he would address it, so they attended some other ses-
sion. Only a few in the audience cared or understood what Morgan was talking
about.William Menardco-chaired thesession atwhichMorganmade hisunexpec-
ted presentation. Menard recalled that ten years later, “I not only did not remem-
ber hearing Jason's famous talk, I didn't remember presiding over the session.”
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One who did remember would later say that he had been “stunned” by Morgan's
presentation and had immediately set to work to follow it up.
2
We can trace the germ of Morgan's idea back to the years immediately after
World War II. By that time, a sea change in research in the earth sciences was
underway. For example, oceanographic research vessels routinely measured some
combination of the following:
• Seafloor topography using sonar
• The strength of the magnetic field using magnetometers towed behind ships
• The pull of gravity
• The geologic structure of the oceanic crust using seismic reflection and refraction
• The stratigraphy of the seafloor using cores recovered by drilling
• The flow of heat through the ocean floor
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