click below
click below
Normal Size Small Size show me how
Geology Vocabulary
8th Grade Science Unit 3 Part 2
Term | Definition |
---|---|
Plate Tectonics Theory | A theory that the Earth's lithosphere (crust and upper mantle) is divided into a number of large plate-like sections. |
Continental Drift Theory | The theory that the continents were once joined together in a giant landmass known as Pangea, broke apart, and have been moving or "drifting" ever since. |
Pangea | The supercontinent that included all current land masses, believed to have been in existence before the continents broke apart during the Triassic and Jurassic Periods. |
Tectonic Plates | The dozen or so plates that make up the surface of the Earth and float on the upper part of the mantle known as the asthenosphere. |
Oceanic Crust | Crust that lies underneath the oceans. Consists mainly of iron and magnesium and is denser than continental crust. |
Continental Crust | Crust that lies underneath the continents. Consists mainly of rocks rich in silica and aluminum. Less dense than oceanic crust. |
Plate Boundary | The area where two or more tectonic plates come together. |
Converging Plates | When two tectonic plates move toward one another |
Convergent Boundary | Plate boundary where two plates move toward each other. |
Divergent Boundary | Plate boundary where two plates move away from each other. |
Transform Boundary | Plate boundary where two plates move past each other in opposite directions. |
Mid-Ocean ridge | Area where new sea floor is formed when lava erupts through cracks in Earth's crust. |
Topographic Map | Map that shows changes in elevation and physical features using contour lines. |
Elevation | The height above or below sea level. |
Contour Interval | The change in elevation between 2 adjacent contour lines. |