what are plate tectonics
Answers
Answer:
the movements of the large sheets of rock (plates) that form the earth's surface; the scientific study of these movements.
Answer:
A tectonic plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere. ... By contrast, oceanic crust is composed of basaltic rocks, which are much denser and heavier.
The outermost part of Earth's structure is known as the lithosphere. The lithosphere consists of the crust and small portion of the upper mantle. The lithosphere is divided into a number of tectonic plates. These plates move and interact with one another, driven by convectional forces within the Earth.
Developed from the 1950s through the 1970s, plate tectonics is the modern version of continental drift, a theory first proposed by scientist Alfred Wegener in 1912. Wegener didn't have an explanation for how continents could move around the planet, but researchers do now. Plate tectonics is the unifying theory of geology, said Nicholas van der Elst, a seismologist at Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York.
There are nine major plates, according to World Atlas. These plates are named after the landforms found on them. The nine major plates are North American, Pacific, Eurasian, African, Indo-Australian, Australian, Indian, South American and Antarctic.
The largest plate is the Pacific Plate at 39,768,522 square miles (103,000,000 square kilometers). Most of it is located under the ocean. It is moving northwest at a speed of around 2.75 inches (7 cm) per year.
There are also many smaller plates throughout the world.