Term | Definition |
Asthenosphere | the soft layer of the mantle on which the tectonic plates move |
Chemical Weathering | the chemical breakdown and decomposition of rocks by natural processes in the environment |
Continental Drift | the hypothesis that a single large landmass broke up into smaller landmasses to form the continents; which then drifted to their present locations; the movement of continents |
Contour Interval | the difference in elevation between one contour line and the next |
Contour Line | a line that connects points of equal elevation on a map |
Convergent Boundary | the boundary between tectonic plates that are colliding |
Deformation | the bending, tilting and bending off of Earth's crust; the change in the shape of rock in response to stress |
Deposition | in geology, the process in which material is laid down |
Divergent Boundary | the boundary between two tectonic plates that are moving away from each other |
Erosion | the process by which wind, water, ice or gravity transports soil and sediment from one location to another |
Geographic Information System | a system for capturing, storing, retrieving, analyzing, manipulating and displaying geographic data |
Global Positioning System | a network of satellites that orbit Earth to measure positions on Earth's surface |
Index Contour | on a map, a darker, heavier contour line that is usually every fifth line |
Lithosphere | the solid, outer layer of Earth that consists of the crust and the rigid upper layer of the mantle |
Magnetic Reversal | the process by which Earth's magnetic north pole and magnetic south pole switch positions periodically; a change in the direction in which Earth's magnetic field points |
Physical Weathering | the mechanical breakdown of rocks into smaller pieces that is caused by natural processes and that does not change the chemical composition of the rock material |
Plate Tectonics | he theory that Earth's outer layer is made up of large, moving pieces called tectonic plates; the theory that explains how plates interact and how those interactions relate to process such as earthquakes and mountain building |
Relief | the difference between the highest and lowest elevations in a given area; the variations in elevation of a land surface |
Remote Sensing | the process of gathering and analyzing information about an object without physically being in touch with that object |
Scale | the relationship between the measurements on a model, map or diagram and the actual measurement or distance |
Sea-Floor Spreading | the process by which new oceanic lithosphere (sea floor) forms when magma rises to Earth's surfaces at mid-ocean ridges and solidifies, as older, existing sea floor moves away from the ridge |
Slope | a measure of the slant of a line; the ratio of rise over run |
Subduction | the process by which one lithospheric plate moves beneath another plate as a result of tectonic forces |
Tectonic Plate | a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle |
Theory | a system of ideas that explains many related observations and is supported by a large body of evidence acquired through scientific investigation |
Topographic Map | a map that shows the surface features of Earth |
Topography | the size and shape of the land surface features of a region, including its relief |
Transform Boundary | the boundary between tectonic plates that are sliding past one another horizontally |
Weathering | the natural process by which atmospheric and environmental agents, such as wind, rain and temperature changes disintegrate and decompose rocks |