When was the theory of plate tectonics discovered?

Question

When was the theory of plate tectonics discovered?

Answer 1

In the late ninteenth and early twentieth centuries, geologists assumed that the Earth's major features were fixed, and that most geologic features such as mountain ranges could be explained by vertical crustal movement, as explained by geosynclinal theory. The discovery of the Americas showed that the opposite coasts of the Atlantic Ocean — or, more precisely, the edges of the continental shelves — have similar shapes and seem once to have fitted together. Since that time many theories were proposed to explain this apparent coincidence, but the assumption of a solid earth made the various proposals difficult to explain.

The discovery of radium and its associated heating properties in 1896 prompted a re-examination of the apparent age of the Earth, since this had been estimated by taking its temperature and assuming that it radiated like a black body. Such calculations assumed that, even if it started at red heat, the Earth would have dropped to its present temperature in a few tens of millions of years. With this new heat source, it was credible that the Earth was much older, and also that its core was still sufficiently hot to be liquid.

Plate tectonic theory arose out of the hypothesis of continental drift first proposed by Alfred Wegener in 1912 and expanded in his 1915 book The Origin of Continents and Oceans, which suggested that the present continents once formed a single land mass which had drifted apart, floating on the molten rocks of the core. But without detailed evidence and calculation of the forces involved, the theory remained sidelined. The Earth might have a solid crust and a liquid core, but there seemed to be no way that portions of the crust could move around -- although later science proved theories proposed by English geologist Arthur Holmes in 1920 that their junctions might actually lie beneath the sea.

The first evidence that crust plates did move around came with the discovery of variable magnetic field direction in rocks of differing ages, first revealed at a symposium in Tasmania in 1956. Initially theorized as an expansion of the global crust,[1] later collaborations developed the plate tectonics theory, which accounted for spreading as the consequence of new rock upwelling, but avoided the need for an expanding globe by recognizing subduction zones and conservative translation faults. It was at this point that Wegener's theory moved from radical to mainstream, and became accepted by the scientific community. Additional work on the association of seafloor spreading and magnetic field reversals by Harry Hess and Ron G. Mason[2][3] pinpointed the precise mechanism which accounted for new rock upwelling.

Following the recognition of magnetic anomalies defined by symmetric, parallel stripes of similar magnetization on the seafloor on either side of a mid-ocean ridge, plate tectonics quickly became broadly accepted. Simultaneous advances in early seismic imaging techniques in and around Wadati-Benioff zones collectively with numerous other geologic observations soon solidified plate tectonics as a theory with extraordinary explanatory and predictive power.

Study of the deep ocean floor was critical to development of the theory; the field of deep sea marine geology accelerated in the 1960s. Correspondingly, plate tectonic theory was developed during the late 1960s and has since been accepted all but universally by scientists throughout all geoscientific disciplines. The theory revolutionized the Earth sciences, explaining a diverse range of geological phenomena.

Answer 2

Theories aren't discovered, they're formulated and postulated.
Plate tectonics is a fact, not a theory.
And you're on the wrong page.
Have a nice day.

Answer 3

The Atlanteans

Answer 4

That question belongs in the Earth Sciences & Geology section, not Astronomy & Space.

Answer 5

Ask a Geologist.

Try this question in: Earth Sciences & Geology

Answer 6

I think it was fully understood sometime in the 60's!

Answer 7

complex subject. lookup onto a search engine. that will could help!