Rigid parts of the Earth's crust and part of the Earth's upper mantle that move and adjoin each other along zones of seismic activity.
Various-sized areas of the earth's lithosphere that move slowly around the mantle's flowing asthenosphere. Most earthquakes and volcanoes occur around the boundaries of these plates. See lithosphere, plate tectonics.
sections of Earth's rigid crust that move as distinct units on a plastic-like mantle on which they rest. As many as twenty different plates have been identified, but only seven are considered to be major (e.g., Eurasian Plate and the South American Plate).
Huge blocks of the earth¡¦s crust that slide around slowly, pulling apart to open new ocean basins or crashing ponderously into each other to create new, larger landmasses.
A rigid section of Earth's crust that moves relative to other such sections on the Earth's surface (see also crust).
The Earth's surface is made up of huge tectonic plates that have moved very slowly during geological history, and continue to move, thus changing the position of continent and oceans. The plates are about 100 kilometres thick and move at a rate of about 1-12 centimetres per year. For more information see Plate tectonics (Box 2 of Nova topic, Looking for clues to our mineral wealth).
Segments of the lithosphere that comprise the surface of the Earth much the way a turtle shell is composed of its plates.
The large, thin, relatively rigid plates that move relative to one another on the outer surface of the Earth.
70-mile-thick blocks of the earth's crust on which the continents ride