what are plate tectonics?

Answer 1

Plate tectonics (from Greek τέκτων, tektōn "builder" or "mason") is a theory of geology developed to explain the observed evidence for large scale motions within the Earth's crust. The theory encompassed and superseded the older theory of continental drift from the first half of the 20th century and the concept of sea floor spreading developed during the 1960s.

The outermost part of the Earth's interior is made up of two layers: the lithosphere comprising the crust and the solidified uppermost part of the mantle. Below the lithosphere lies the asthenosphere which comprises the inner viscous part of the mantle. The mantle behaves like a superheated and extremely viscous liquid.

The lithosphere essentially floats on the asthenosphere. The lithosphere has broken up into what are called tectonic plates - in the case of Earth, there are ten major and many minor plates. These plates move in relation to one another at one of three types of plate boundaries: convergent, divergent, and transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries.

Answer 2

Plate Tectonics is a theory advanced in the 1970s that explainsthe motion of crustal and upper mantle plates riding on the circulating mantle. It replaced the Theory of Continental Drift which had no mechanism to explain how the continents "drifted". The correct name of the theory is the Theory of Seafloor Spreading and Plate Tectonics.

Answer 3

the first two answers are right on the money except that plate tectonics is no longer a theory is has become a fact.

Answer 4

You have already received two very good answers. If you want to know more, do some research. The Internet is at your fingertips. Enjoy!

Answer 5

As a geologists, I don't have much to add. The first two were good answers