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Unit 3: Plate Tectonics and Volcanoes

Terms in this set (39)

Atmosphere
The envelope of gases that surrounds Earth
Biosphere
All living things, whether in the air, in the oceans, or on and beneath the land surface.
Convection
the slow circulation of subcrustal material, thought to be the mechanism by which tectonic plates are moved
Convergent Boundary
A plate boundary where two plates move toward each other
Continental Drift
The hypothesis that the continents slowly move across Earth's surface
Crust
The layer of rock that forms Earth's outer surface
Deep Ocean Trench
A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
Density
a measure of the compactness of a substance, expressed as its mass per unit volume.
Divergent Boundary
A plate boundary where two plates move away from each other
Earthquakes
the shaking that results from the movement of rock beneath Earth's surface
Explosivity
a relative measure of the explosiveness of volcanic eruptions.
Fault
A break or crack in Earth's lithosphere along which the rocks move
Fossil
A trace of an ancient organism that has been preserved in rock
Geosphere
another name for the lithosphere; a rigid layer made up of the uppermost part of the mantle and the crust; the solid portion of the earth
Global Positioning System (GPS)
a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites
Hydrosphere
the water on or surrounding the surface of the globe, including the water of the oceans and the water in the atmosphere.
Lithosphere
A rigid layer made up of the uppermost part of the mantle and the crust
Magma
hot molten rock, usually formed in the earth's upper mantle, some of which finds its way into the crust and onto the earth's surface, where it solidifies to form igneous rock
Mantle
The layer of hot, solid material between Earth's crust and core
Mantle Convection
A cycle of heating, rising, cooling, and sinking of plasticlike rock transferring heat from the core and the mantle
Mid-ocean Ridge
An undersea mountain chain where new ocean floor is produced
Mountain belts
These consist of several mountain ranges that run roughly parallel to each other. They typically are thousands of kilometers long and hundreds of kilometers across and parallel continental coastlines.
Mountain ranges
a series of adjoining mountains or of lines of mountains of similar origin
Oceanic plates
A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of oceanic crust
Pangaea
The name of the single landmass that broke apart 200 million years ago and gave rise to today's continents
Plate
A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust
Plate boundaries
When plates move, they can interact in several ways. There are three types; plate can move toward each other or collide (convergent), pull apart (divergent) or slide alongside one another (transform).
Plate Tectonics
The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle
Pressure
The force exerted on a surface divided by the total area over which the force is exerted
Radioactive Decay
The spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles. The rate of decay of radioactive substances such as carbon 14 or uranium is measured in terms of their half-life
Sonar
A device that determines the distance of an object under water by recording echoes of sound waves
Sea-floor spreading
The process by which molten material adds new oceanic crust to the ocean floor
Subduction
The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
Tectonic Plates
A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust
Thermal energy
the total energy of motion in the particles of a substance
Transform Boundary
A plate boundary where two plates move past each other in opposite directions.
Transform faults
A strike-slip fault, common in mid-ocean ridge regions, in which there has been a sudden change in the form or direction of displacement.
Upper Mantle
the soft layer of the mantle on which the lithosphere floats; also known as the asthenosphere
Volcanoes
Cone-shaped hills or mountains formed when hot magma, solids, and gas erupt onto Earth's surface through a vent.
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