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ELL Earth Sci 4
Plate Tectonics
| Term | Definition |
|---|---|
| continental drift | hypothesis stating that continents once formed a single land mass, broke up and drifted to their current locations |
| Pangaea | single land mass thought to have been the origin of all continents |
| Panthlassa | giant ocean surrounding Pangaea |
| Mid-Atlantic Ridge | undersea mountain range with a steep, narrow valley along its center |
| mid-ocean ridges | system of undersea mountain ranges that wind around the Earth |
| seafloor spreading | movement of the ocean floor away from either side of a mid-ocean ridge |
| plate tectonics | theory that the lithosphere is made up of plates and float on the asthenosphere |
| lithosphere | thin outer shell of the Earth consisting of the crust and rigid upper mantle |
| asthenosphere | zone of mantle beneath the lithosphere that consists of slowly flowing solid rock |
| divergent boundary | boundary formed by two lithospheric plates that are moving apart |
| convergent boundary | border formed by the collision of two lithospheric platess |
| subduction zone | region where one lithospheric plate moves under another |
| transform boundary | boundary formed where two lithospheric plates slide past each other |
| convection | transfer of heat through the movement of heated material |
| convection current | movement of fluid caused by uneven heating |