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plate tectonics

(Encyclopedia)CE5 Plate tectonics: Map of the world showing major plates and plate boundaries CE5 Plate tectonics: Schematic model of the oceanic crust, showing the three types of plate boundaries plate tect...

plate

(Encyclopedia)plate: see electron tube.

Sheffield plate

(Encyclopedia)Sheffield plate, metalware of copper, silver-plated by fusion, originated at Sheffield, England. This process of plating was discovered c.1742 by a Sheffield cutler, Thomas Boulsover, who found while ...

Plate, River

(Encyclopedia)Plate, River: see Plata, Río de la. ...

mid-ocean ridge

(Encyclopedia)mid-ocean ridge: see plate tectonics. ...

San Andreas fault

(Encyclopedia)San Andreas fault, great fracture (see fault) of the earth's crust in California. It is the principal fault of an intricate network of faults extending more than 600 mi (965 km) from NW California to ...

chromite

(Encyclopedia)chromite krōˈmīt [key], dark brown to black mineral. It is an iron-chromium oxide, FeCr2O4, with traces of magnesium and aluminum. Its crystals are octahedral, but rare; it usually occurs as irregu...

subduction zone

(Encyclopedia)subduction zone, large-scaled narrow region in the earth's crust where, according to plate tectonics, masses of the spreading oceanic lithosphere bend downward into the earth along the leading edges o...

rift valley

(Encyclopedia)rift valley, elongated depression, trough, or graben in the earth's crust, bounded on both sides by normal faults and occurring on the continents or under the oceans. The central flat block forming th...

Wilson, J. Tuzo

(Encyclopedia)Wilson, J. Tuzo (John Tuzo Wilson), 1908–93, Canadian geologist and geophysicist, b. Ottawa, Ph.D. Princeton (1936), M.A. Cambridge (1940). He worked for the Geological Survey of Canada (1936–39) ...