Some of
milestones in the development and acceptance of the theory of plate tectonics. Note
that the dates may represent a period rather than one specific year. Also, the
work may have been carried out at more than the one location given.
1858. Antonio Snider-Pellegrini
(American geographer living in Paris). Constructed maps
that demonstrated how the American and African continents once fit together and
later separated. Based on plant fossils in both Europe and America that were
identical.
1914. Joseph Barrell (Yale).
Developed an earth model based on the presence of gravity anomalies over
continental crust. He inferred that there must exist a strong, solid upper
layer (the “lithosphere”) above a weaker layer which could flow (the “asthenosphere”).
1915.
Alfred Wegener (University of Hamburg). Hypothesized that the continents are
slowly drifting around the Earth, based on the observation that the various
large landmasses almost fit together like a jigsaw puzzle.
1919. Arthur Holmes (University of Durham).
Proposed that the earth's mantle contained convection cells that
dissipated radioactive heat and moved the crust at the surface.
1935.
Boris Choubert (French Research
Institute for Development). Published a reconstruction of the relative
positions of America, Africa and Europe, based on the 1000-meter isobath which
produced a better representation of the limits of the continents.
1951. Keith Runcorn (Cambridge) & P.M.S.
Blackett (Imperial College).
Compiled paleomagnetic reconstructions
of the relative motions of Europe and America which revived the theory of
continental drift and was a major contribution to plate tectonics.
1953. Maurice Ewing, Marie Tharp and Bruce Heezen
(Lamont-Doherty Earth Observatory of Columbia University). Carried out detailed mapping of the
Mid-Atlantic Ridge using seismic surveying, coring etc.
1962. Harry Hess (Princeton). Proposed that the seafloor itself
moves, carrying the continents with it, as it expands from a central axis.
1963. Frederick John Vine (Cambridge).
Showed that magnetic reversals frozen into the sea floor rocks can be
seen as parallel strips as you move perpendicularly away from the ridge crest.
1965. John Tuzo Wilson (University of Toronto). Proposed the transform fault, a major plate
boundary where two plates move past each other horizontally (e.g. the San
Andreas Fault).
1968.
Xavier Le Pichon (Collège de France, Paris). Developed a complete model based on six
major plates with their relative motions, which marked the final acceptance by
the scientific community of plate tectonics.
