Chapter 5 Vocabulary - Plate Techtonics

Conduction

the process by which heat/electricity is directly transmitted through collision between neighboring atoms/molecules

Continental Crust

thick part of Earth's crust that forms large landmasses, about 30,000 to 35,000 km thick, less dense, 2.7 gm/cm^3

Convection

the movement caused within fluid by the tendency of hotter (less dense) material to rise and colder (denser) material to sink under the influence of gravity

Convection Cell

the movement of convection - a self-contained convective zone in a fluid which upward motion of warmer fluid in the center is balanced by downward motion of cooler fluid at the periphery

Core

the dense central region of a planet, especially the nickel-iron inner part of the Earth

Crust

the thin outer shell of rock,

Lithosphere

the rigid outer part of the Earth consisting of the crust and upper mantle, about 30 plates, moves about 2 inches a year

Mantle

between crust and outer core, rocky shell, 2890 km (1800 mi) thick, 85% of Earth's volume, has upper and lower mantle

Meteorite

a meteor that survives its passage through the Earth's atmosphere, the part that strikes the ground, made of iron/nickel, used to find out what was in Earth's core

Oceanic Crust

thin part of Earth's crust that lies under the ocean, consist of basalt rock + sediments, 5 to 12 km thick, denser, 3.1 gm/cm^3

P-Wave

aka. compressional wave, seismic body that shakes the ground back and forth in the same direction and opposite direction the wave is moving, longitude wave, goes through solid and liquid

S-Wave

aka. secondary waves that occur during seismic activity, shear waves in nature, comes after primary waves, transversal wave, doesn't go through liquid

Seismic Wave

an elastic wave in the Earth produced by an earthquake or other means, used to find plate boundaries with earthquakes

Apparent Polar Wave

magnetite crystals point toward north when they solidify. when the continent moves the crystals no longer point north.
the perceived movement of the Earth's paleo-magnetic poles relative to a continent while regarding the continent being studied as fixed in position

Continental Drift

the gradual movement of the continents across the Earth's surface through geological time, caused by convention currents in the mantle

Magnetic Field

a region around a magnetic material or moving electric charge within which the force of magnetism acts, a non-contact field that goes above the surface

Magnetic Polarity

the state of being a north pole or south pole, the direction of the magnetic field

Magnetite

a gray-black magnetic material which consists of oxide of iron and is an important form of iron ore, aligns with magnetic field

Magnetometer

an instrument used for measuring magnetic forces, especially the Earth's magnetism

Batholith

a very large igneous intrusion extending deep in the Earth's crust, when the crust subducts in the mantle - the other is pointing up

Continental Arc

a type of volcanic arc occurring as an "arc-shape" topographic high region along a continental margin, in the ocean

Continental Rifting

a thinning process of the lithosphere leading to the rupture of the continent and the formation of a mid-oceanic ridge and sea floor spreading, divergent plates on a continent

Convergent Plate Boundary

aka. destructive boundary, is an area on Earth where two or more lithospheric plates collide

Divergent Plate Boundary

aka. constructive boundary, linear feature that exists between two tectonic plates that are moving away from each other

Epicenter

the point on the Earth's surface vertically above the focus of an earthquake

Hotspot

a small area or region with a relatively hot temperature in comparison to its surroundings, the core releases energy into the mantle that melts the crust and can create volcanoes. Yellowstone is a hotspot, there are more in the ocean

Intraplate Activity

relating to or occurring within the interior of a tectonic plate, an intraplate earthquake

Island Arc

when two oceanic plates converge and the denser one subducts, a curved chain of volcanic islands located at a tectonic plate margin, typically with a deep ocean trench on the convex side

Plate

the outer shell, major separate rigid blocks, oceanic + continental

Plate Boundary

the location where two plates meet (earthquakes + creation of topographic features), found with seismic waves

Plate Tectonics

a theory about the movement of plates. also explains the structure of Earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates which move slowly over underlying mantle

Subduction

the sideways and downward movement of the edge of a plate of the Earth's crust into the mantle beneath another plate

Subduction Zone

a convergent plate boundary, one plate subducts beneath the other, usually because it is denser

Super Continental Cycle

aka. Wilson Cycle, the quasi-periodic aggregation and dispersal of Earth's continental crust. Pangea split into Laurasia and Gondwanaland

Transform Fault

a strike-slip fault occurring at the boundary between two plates of the Earth's crust, the plates are sliding past each other, small earthquakes are safer than no earthquakes

Transform Plate Boundary

conservative plate boundaries where lithospheric plates slide past each other where the crust is neither destroyed nor formed