Term | Definition |
crust | the outmost layer of the earth is the crust it is 5 to 100 km thick |
mantle | the layer of earth between the crust and the core contains most of earths mass |
core | the layer of the earth that extends from below the mantle to the center of the earth |
lithosphere | the outmost rigid layer of the earth |
asthenosphere | a plastic layer of the mantle on which pieces of lithosphere move made of solid rock |
mesosphere | extends from the bottom of the asthenosphere to the earth's core |
tectonic plate | a block of lithosphere that consists of the crust and the rigid outmost part of the mantle |
continental drift | the hypothesis that states the continents once formed a single land mass broke up, and drifted to their present locations |
Pangaea | existed when some of the earliest dinosaurs roamed the earth - a continent surrounded by a sea called panthalassa |
Laurasuia - Gondwana | two continents that Pangaea broke up into |
Eurasia | a continent that used to be connected to North America but separated from the other continents we know today |
sea floor spreading | process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies |
Plate tectonics | the theory that the earths lithosphere is divided into tectonic plates that move around on top of the asthenosphere |
convergent | when two tectonic plates collide |
divergent boundary | when two tectonic plates separate |
transform boundary | when two tectonic plates slide past each other horizontally |
gps | also known as the global positioning system uses radio waves to sense things happening on earth |
ridge push | when the oceanic lithosphere slides downhill under the force of gravity |
slab pull | when oceanic lithosphere sinks and pulls the rest of the tectonic plate with it |
convection | causes the oceanic lithosphere to move sideways and away from the mid ocean ridge |
compression | type of stress that occurs when an object is squeezed such as when two tectonic plates collide |
tension | is sress that occurs when forces act to stretch an object |
folding | the bending of rock layers because of stress in the earth's crust |
fault | is a surface along which rocks break and slide past each other |
uplift | the rising of regions of the earth's crust to higher elevations |
subsidence | the sinking of regions of the earth's crust to lower elevations |