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Unit 3 Vocabulary
Tectonic Plates
Term | Definition |
---|---|
Asthenosphere | The lower part of the crust and upper part of the mantle |
Subduction | When denser plates sink under less dense plates |
Seafloor Spreading | When lava in the ocean hardens and forms a rock at a mid ocean ridge and pushes older crust back |
Mantle convection | The circulation of warm less dense material and cold dense material |
Ridge push | When lava hardens and pushes away old crust |
Slab pull | When old and colder plates are pulled under newer ones |
Lava | Magma that's exited the earth's crust |
Magma | Molten rock and minerals in earth's crust |
Tectonic Plate | Giant irregularly shaped slab of solid rock |
Theory of Continental Drift | The theory that the continents are slowly drifting apart |
Convergent boundary | When two plates push together in the same direction; often forms volcanic mountains |
Divergent boundary | When two plates are pulled apart/pushed apart and form ridges or rift valleys |
Transform boundary | When two plates rub against each other in opposite directions; forms faults and causes earthquakes |
Hot Spot | Hot areas on Earth's surface where plumes of mantle rise to the surface |
Epicenter | Point directly above the focus of an earthquake |
Focus | The point of the first rupture of a fault during an earthquake |
Pangaea | Theory that the continents were once whole called a supercontinent |
Geohazard | Geological occurrences where land falls, moves, or shifts |
Reverse Fault | Compression forces plates to move in opposite directions (upward) |
Strike-slip fault | Shearing causes horizontal movement along fault |
Normal Fault | Tension causes plates to slip horizontally downward |
Compression | Stress that's aimed to the center of a rock mass |
Tension | Stress that pulls rocks in two separate directions |
Shearing | The shifting of two plates or rocks against one another |
Felsic | Igneous rocks with many elements that form feldspar and etc, |
Mafic | Igneous rocks with lots of magnesium and iron |