click below
click below
Normal Size Small Size show me how
Chapter 9
Term | Definition |
---|---|
Subduction | The movement of one tectonic plate underneath another at a convergent plate boundary |
Hot spot | A term used to describe a specific point located near the middle of a tectonic plate that experiences volcanic activities |
Mantle convection | Large convection cells that are believed to exist in the earths upper mantle |
Anticline | A type of fold in rock strata that forms an arched shape |
Syncline | A U-shaped fold or depression in rock |
Lateral force | Forces that push in on sometimes from both sides |
Strata | Horizontal layers of sedimentary rocks |
Geosyncline | A bowl shaped depression in the earths crust formed from the deposition of large amounts of sediments |
Fault | A large break or crack in a large rock mass formed by tectonic stress that results in the displacement of rock strata |
Rift valley | A valley that forms along a divergent plate boundary where two tectonic plates are spreading apart |
Mid-ocean ridges | Divergent tectonic plate boundaries located on the ocean floor where new crust is formed that pushes on the two plates causing them to spread apart |
Isostacy | The theory that explains how the earths crust is in balance causing the continents to float at different levels on the asthenosphere below much different sized blocks of wood floating at different levels in water |
Magnetic north | The direction on the earth toward which a magnetic needle points which is slightly different from the geographical North Pole which is located directly on earths axis of rotation |
Plate boundaries | Specific areas on the earths crust where two or more tectonic plates interact with each other |
Volcanic arc | A chain of volcanic islands that forms near a convergent plate boundary located below the ocean |