Download Plate Tectonic Vocabulary

Plate Tectonic Vocabulary
Earthquake: a shaking or movement of Earth’s surface; caused by the release of stored energy
along a fault. Earthquakes occur along plate boundaries.
Energy: The ability to cause change. Example: a boulder rolling down-hill has energy.
Fault: A break in rock along which rock slabs have moved. The shifting of Earth’s tectonic
plates can produce a fault, along which earthquakes may occur.
Tectonic plate: One of the slabs that make up Earth’s crust and upper mantle. Some of Earth’s
tectonic plates carry continents.
Plate boundary: A place where the plates that make up Earth’s crust and upper mantle either
move together or move apart or move past one another.
Theory: An idea based on a large body of evidence that explains how something happens or
works.
Theory of continental drift: A theory that states that the continents were a single landmass at one
time in the past and have moved over time to their present positions. The theory of continental drift
was first suggested by Alfred Wegener.
Theory of plate tectonics: The theory that Earth’s lithosphere is broken into enormous slabs, or
plates, that are in motion. Scientists use the theory of plate tectonics to explain how Earth’s
continents drift.
Lithosphere: The rigid, rocky outer layer of Earth, including the crust and the solid, top part of
the mantle. The lithosphere is about 100 km (60 miles, about the distance from Oroville to
Sacramento)
Crust: The thin, rocky outer layer of Earth. Under the oceans the crust can be as thin as 10 km (6
miles) and where there are mountains the crust can be as thick as 65 km (40 miles).
Asthenosphere: The region of the mantle just below the lithosphere. It is the upper part of the
mantle that is hot, soft (partially melted) and slightly fluid (has plastic like properties and is
able to flow).
Mantle: The layer of the Earth between the crust and the core. The mantle is the thickest layer of the
Earth (2,900 km or 1,740 miles)
Core: The innermost, densest layer of Earth. The core is made up of two parts, the outer core and the
inner core. The outer core is molten and is made up of iron and some less dense material. The
inner core is solid and is mostly iron and possibly some nickel.
Density: The amount of mass in a given volume of matter. The density of iron is greater than
that of wood.
Matter: Anything that has mass and takes up space.
Convection: The transfer of heat energy through liquids and gases, fluids, by moving particles.
Convection current: The pathway along which energy travels through a fluid.
Convergent boundary: A place where the plates that make up Earth’s crust and upper mantle
collide or come together. Layers of rock may bend or break at a convergent boundary.
Divergent boundary: A place where the plates that make up Earth’s crust and upper mantle move
away from one another. Most divergent boundaries are found on the ocean floor.
Transform-fault boundary: A place where the plates that make up Earth’s crust and upper mantle
move past one another.
Sea floor spreading: The process by which new ocean floor is continually being formed as
magma rises to the surface and hardens into rock. Sea-floor spreading occurs as magma fills the
space between separating plates.
Mid-ocean ridge: A chain of mountains on the ocean floor. New ocean floor forms at the midocean ridge where the sea floor is spreading.
Pangaea: A supercontinent that existed about 200 million years ago. Pangaea broke apart into
several continents.
Rifting: The process by which magma rises to fill the gap between two plates that are moving
apart. Rifting in eastern Africa may split the continent into two parts.
Geothermal energy: Energy derived from the heat of Earth’s interior.
Magma: The hot, molten rock deep inside Earth.
Lava: Magma that flows out onto Earth’s surface from a volcano.
Magnetic Field: The space around a magnet within which the force off the magnet is exerted.
Magnetic reversal: The switching or changing of Earth’s magnetic poles such that the north
magnetic pole becomes located at the south magnetic pole’s position and vice versa. Scientists
have found evidence of magnetic reversals in layers of rock along the ocean floor.
Sediment: Earth material, such as soil and rock fragments formed by weathering.
Seismograph: An instrument that records the intensity, duration, and nature of earthquake waves.
Subduction: The process of moving part of the lithosphere down into the mantle along a
convergent boundary. (Note: This word is not used in the text book but it is important)