Essay about the power of transform faults


   Here is a description of the power of transform fault models, excerpted from a piece I wrote in 2001, remembering those amazing times.

    For the summer of 1965, ... I applied for and got an internship at the Woods Hole Oceanographic Institute. I admit, I was drawn primarily by the romance of the sea and ships. I didn't know enough to realize that the marine scientists were about to unleash a revolution upon the geo-world. When I saw a number of the Woods Hole staff preparing for an Upper Mantle Committee meeting in Ottawa, Canada, I asked my mentor, Bracket Hersey, if I could go too. He said "Sure. Why not?" and found me travel funds. The meeting was concentrated on the geophysics of the oceans and the various mysteries therein. The list of sessions included all the right things: mid-ocean ridges and rifts, fracture zones, trenches and island arcs, magnetic stripes. They knew what needed explaining, just not quite how to do it. Most of the major players in this small field were there and I greatly enjoyed meeting them and putting their faces and their quirkinesses to their names. The whole meeting was exciting, but the presentation that made the biggest impression on me was the one by J. Tuzo Wilson, about transform faults. Tuzo was a wonderful showman with a great twinkle in his eye. After he had explained his idea, he passed out paper diagrams with two mid-ocean ridges connected by a transform fault. It said "cut here", "fold here", "pull here". We all laughed, and I felt embarrassed (kindergarten games at this august scientific meeting?), but I took the paper back to the privacy of my hotel room and cut and folded and pulled and, wow: the light bulbs really went on in my brain. The simple geometry of the transform faults with their fracture zones holds the key to the geometry of formation of all the ocean basins - right there in that little piece of paper. I've been handing out versions of that diagram to students ever since, and urging them, after they stop laughing, to cut, fold and pull.

Tuzo's presentation covered the material in Wilson, J. Tuzo, 1965, A new class of faults and their bearing on continental drift, Nature, v. 207, no. 4995, p 343-347.


Atwater, Tanya, 2001, Chapter 15: When the Plate Tectonic Revolution Met Western North America, pages 243-263 in Plate Tectonics, An Insider's History of the Modern Theory of the Earth, Naomi Oreskes, ed., Westview Press, 424 pages.


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