John Dewey: geology before and after plate tectonics

John Dewey describes the effect on the discipline of geology of plate tectonics in the 1960s.

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Were there things that you’d seen and mapped in – in Western Ireland during your PhD and afterwards that were completely mysterious or completely unexplained before plate tectonics and then explicable afterwards? 

Oh yes, I mean the whole structure of the so called South Mayo Trough, this thing I mentioned, this big Ordovician syncline with the Silurian rocks on top, particularly Ordovician. I mean it was just – it was a – it was just a sort of – a hole in the ground in which sediments accumulated, that was clear ‘cause of the thickness, it was enormous thickness of sediments, and volcanics, there were sort of, you know, andesites and – and they made no real sense. Because part of the fact was of course that until plate tectonics and well until the great oceanographic cruises of the late ‘50s and ‘60s so little was known about the ocean floor and it was very hard to draw analogies between when I was doing my PhD in the ‘50s, it was hard to draw an analogy between the South Mayo Trough and anything in the modern oceans because we didn’t know very much about the modern oceans. We knew there were trenches I suppose and ridges but it was – details were very very obscure. So I suppose the plate tectonics really began to – before plate tectonics there wasn’t really very much in – much what’s the word, rationale, there was little rationale in explaining geology, except bits of it, volcanoes, turbidites, structures, you know, you could describe these things but it was very hard to put them into any rational framework to understand them. And then plate tectonics suddenly exploded, I mean suddenly here’s a rational explanation for most of the geology of the world, and not just the modern world but the old stuff as well.

  • Interviewee John Dewey
  • Duration 00:02:02
  • Copyright British Library Board
  • Interviewer Paul Merchant
  • Date of interview 8/27/2012
  • Shelfmark C1379/83

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