History of Plate Tectonics Theory Timeline

In 1941, Otto Ampferer described, in his publication 'Thoughts on the motion picture of the Atlantic region', processes that anticipated seafloor spreading and subduction decades before these concepts became mainstream.

Image source: Otto Ampferer

In 1947, a team of scientists led by Maurice Ewing utilizing the Woods Hole Oceanographic Institution's research vessel Atlantis and an array of instruments, confirmed the existence of a rise in the central Atlantic Ocean, and found that the floor of the seabed beneath the layer of sediments consisted of basalt, not the granite which is the main constituent of continents.

Image source: Maurice Ewing

A second piece of evidence in support of continental drift came from data on the bathymetry of the deep ocean floors and the nature of the oceanic crust such as magnetic properties, with the development of marine geology giving evidence for the association of seafloor spreading along the mid-oceanic ridges and magnetic field reversals, published between 1959 and 1963 by Heezen, Dietz, Hess, Mason, Vine & Matthews, and Morley.

Image source: Seafloor spreading

This was described in the crucial paper of Bruce Heezen (1960) based on his work with Marie Tharp, which would trigger a real revolution in thinking about the ocean floors and their role in global geology.

Image source: Marie Tharp

Dietz and Hess (the former published the same idea one year earlier in Nature, but priority belongs to Hess who had already distributed an unpublished manuscript of his 1962 article by 1960) were among the small number who really understood the broad implications of sea floor spreading and how it would eventually agree with the unconventional ideas of continental drift and the mobilistic models proposed by previous workers like Holmes.

Image source: Harry Hammond Hess

Mason and co-workers in 1961 documented the striking magnetic striping of the ocean floor, though they did not find an explanation for these data in terms of sea floor spreading, like Vine, Matthews and Morley a few years later.

Only four years after the maps with the 'zebra pattern' of magnetic stripes were published, the link between sea floor spreading and these patterns was recognized independently by Lawrence Morley, and by Fred Vine and Drummond Matthews, in 1963 — the Vine–Matthews–Morley hypothesis.

Image source: Vine–Matthews–Morley hypothesis

The study of global seismicity greatly advanced in the 1960s with the establishment of the Worldwide Standardized Seismograph Network (WWSSN) to monitor compliance with the 1963 treaty banning above-ground testing of nuclear weapons. Improvements in seismic instruments had already shown earthquakes concentrate along oceanic trenches and spreading ridges.

In 1965, Tuzo Wilson, who had been a promoter of the sea floor spreading hypothesis and continental drift from the very beginning, added the concept of transform faults to the model, completing the classes of fault types necessary to make the mobility of the plates on the globe work out.

Image source: Transform fault

All the evidence from the ocean floor and continental margins made it clear around 1965 that continental drift was feasible. A symposium on continental drift was held at the Royal Society of London in 1965 which must be regarded as the official start of the acceptance of plate tectonics by the scientific community, with abstracts issued as Blackett, Bullard & Runcorn (1965).

The theory of plate tectonics was defined in a series of papers between 1965 and 1967. In 1967, at the American Geophysical Union's meeting, W. Jason Morgan presented the model of rigid plates moving across Earth's surface, consolidating the modern theory.

In 1966 Wilson published the paper that referred to previous plate tectonic reconstructions, introducing the concept of what became known as the 'Wilson Cycle' — the opening and closing of ocean basins over geologic time.

Image source: Wilson Cycle

Since 1990 an alternative interpretation has been mainly advocated by Doglioni and co-workers (Doglioni 1990), such as in a more recent 2006 study, where scientists reviewed and advocated these ideas challenging aspects of the standard plate driving force model.

Observations made of the magnetic field of Mars by the Mars Global Surveyor spacecraft in 1999 showed patterns of magnetic striping discovered on this planet, suggesting possible ancient tectonic activity beyond Earth.

Image source: Mars Global Surveyor

Other authors evoked external driving forces due to the tidal drag of the Moon and other celestial bodies. It has been suggested in Lovett (2006) that tidal effects may explain why Venus and Mars have no plate tectonics, as Venus has no moon and Mars' moons are too small to have significant tidal effects on the planet.

In 2007, two independent teams of researchers came to opposing conclusions about the likelihood of plate tectonics on larger super-Earths, with one team saying that plate tectonics would be episodic or stagnant and the other saying that plate tectonics is very likely on super-Earths even if the planet is dry.

Image source: Super-Earth

Especially since 2000, with the emergence of computational models reproducing Earth's mantle behaviour to first order, following upon the older unifying concepts of van Bemmelen, authors re-evaluated the important role of mantle dynamics. The debate is still open, and a 2022 paper by Hofmeister et al. continued to question the conventional driving mechanisms.