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unit 3 vocab abriya
plate tectonics
term | Definition |
---|---|
Asthenosphere | the upper layer that is part of the earth's mantle, known to be mechanically weak, and below the lithosphere. |
Subduction | the process of which one tectonic plate falls between another. |
Seafloor Spreading | the hypothesis that new ocean crust is being formed at mid-ocean ridges and destroyed by the deep sea trenches, this occurs in a continuous cycle of magma intrusion and spreading. |
Mantle convection | the very slow motion of earths mantle that is caused by convection currents that carry heat from the interior to the earths surface. |
Ridge Push | tectonic plates that are associated with convection currents in earths mantle that occurs when the weight of an elevated ridge pushes an oceanic plate towards a subduction zone. |
Slab pull | tectonic process associated with convection currents in earths mantle that occurs as the weight of the subducting plate |
lava | magma that flows out onto the earths surface |
magma | hot fluid below or within the earths crust from which lava and other igneous rock is formed when cooling. |
tectonic plate | huge pieces of earths crust that covers its surface and fit together at there edges. |
theory of continental drift | a theory that was explained by Alfred Wegener that all continents were once put together as one. |
convergent boundary | place where two tectonic plates are moving toward each other associated with trenches, island arcs, and folded mountains. |
divergent boundary | place where two of earths tectonic plates are moving apart, associated with volcanism, earthquakes and high heat flow, and is found on seafloor. |
transform boundary | place where two tectonic plates slide horizontally past each other, is characterized by long faults and shallow earthquakes. |
hotspot | usually hot in earths mantle where high-temperature plumes of mantle material rise toward the surface. |
epicenter | point on earths surface directly above the surface of an earthquake. |
focus | point of the initial fault rupture where an earthquake originates that usually lies at least several kilometers beneath the earths surface. |
Pangaea | ancient landmass made up of all continents that begin to break apart about 200 mya. |
geohazard | enviromental conditions that involve long-term or short-term geological process. |
reverse fault | in which the hanging wall has moved upward relative to the foot wall, occur when two blocks of rock are forced together by compression. |
strike-slip fault | a fault in which rock strata are displaced mainly in a horizontal direction, parallel to the line of the fault. |
normal fault | the hanging wall has moved downward relative to the footwall, occurs when two blocks of rock are pulled apart by tension. |
compression | the action or state of being squished down or made smaller or more pressed together. |
tension | the state of being stretched or strained. |
shearing | a motion of two rock surfaces against each other. |
felsic | consisting of or chiefly consisting of feldspar or feldspathiod quartz. |
mafic | of or relation to being a group of usually dark colored minerals rich in magnesium and iron. |