| Term | Definition |
|---|
| Alfred Wegner | developed the Continental Drift theory |
| Harry Hess | found a way to explain the movement of the continents |
| Sea floor spreading | new ocean crust is formed at mid-ocean ridges, or divergent plate boundaries, the old ocean crust is destroyed at the convergent plate boundaries in the ocean trenches |
| Subduction zones | region where one lithospheric plate moves under another |
| Pangaea | Wegner hypothesized that the continents one formed part of a single landmass, which he named Pangaea, meaning "all lands" |
| Mid-ocean ridge | undersea mountain range with a steep, narrow valley along its center |
| Trench | deep valley in the ocean floor |
| Rift valley | steep, narrow valley formed as lithospheric plates separate |
| Convergent boundary | border formed by the direct collision of two lithospheric plates |
| Divergent boundary | boundary formed by two lithospheric plates that are moving apart |
| Transform fault | boundary formed where two lithospheric plates slide past each other |
| Anticline | up-curved fold in horizontal rock layers |
| Syncline | down-curved fold in horizontal rock layers |
| Reverse fault | fault in which the hanging wall moves up relative to the footwall |
| Thrust fault | type of reverse fault in which the fault plane is nearly horizontal rather than vertical |
| Normal fault | fault in which hanging wall moves down relative to the footwall |
| Hanging wall | rock above a normal fault plane |
| Foot wall | rock below a fault plane |
| Strike-slip fault | fault in which the rock on wither side of a fault plane slides horizontally |
| Compression | stress that squeezes crystal rocks together |
| Tension | stress that pulls rock apart |
| Shearing | stress that pushes rocks in the opposite horizontal direction |
| Mountain belts | group of large mountain systems |
| Plateaus | large area of flat-topped rocks high above sea level |
| Folded mountains | landform created when tectonic movements bend and uplift rock layers |
| Fault-block mountains | mountain formed when faulting breaks the earth's crust into large blocks and the blocks are uplifted and tilted |
| Grabens | long, narrow valley formed by faulting and downward slippage of a crystal block |
| Volcanic mountains | mountain formed when molten rock erupts onto the earth's surface |
| Dome mountains | landform created when molten rock pushes up rock layers on the earth's surface and the layers then are worn away in places, leaving separate high peaks |
| Isostatic adjustment | up-and-down movements of the earth's crust to reach isostasy |
| Epicenter | point on the earth's surface directly above the focus of an earthquake |
| Focus | area along a a fault which slippage first occurs, initiating an earthquake |
| Elastic-rebound theory | theory that rocks that are strained past a certain point will fracture and spring back to their original shape |
| Seismograph | instrument used to detect and record seismic waves |
| Richter Scale | scale that expresses the magnitude of an earthquake |
| Shield cones | volcanic deposit of hardened lava with a broad base and gentle slopes |
| Composite cones | also called stratovolcano, steep-sloped volcanic deposit with alternating layers of hardened lava flows and tephra |
| Cinder cones | steep-sloped deposit of solid fragments ejected from a volcano |
| Hot spots | area of volcanism within a lithospheric plate |
| Tephra | all the rock fragments ejected from a volcano |
| Pyroclastic flows | also called tephra, all of the rock fragments ejected from a volcano |
| Lahars | mudflow |
Combine with other sets
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