Into the Moving Earth Flashcards

Flashcards about the Earth's layers and plate tectonics.

Crust

Outermost layer of Earth, including continents.

Lithosphere

Crust and the uppermost part of the mantle.

Tectonic Plates

Major blocks that compose the lithosphere.

Mohorovicic Discontinuity

Discontinuity between the crust and upper mantle.

Mantle

Hot layer below the crust.

Asthenosphere

Magma, 180km thick.

Convection Current

Deformation and reshaping of the asthenosphere driven by heat energy.

Gutenberg Discontinuity

Discontinuity between the lower mantle and outer core.

Outer Core

Liquid, molten nickel and iron.

Lehmann Discontinuity

Discontinuity between the outer core and inner core.

Inner Core

Solid iron.

Seismic Waves

Detected and recorded by seismographs and seismograms.

Body Waves

Travels only on the inner layers; important in providing information about the Earth’s interior.

Surface Waves

Travels only on the surface; important in assessing earthquake damage and perceived earthquake strength.

Primary Waves (P-waves)

Passes through solid and liquid; fastest.

Secondary Waves (S-waves)

Passes only through solids; slower, transverse waves.

Pangaea

The first large landmass of Earth.

Contraction Theory

Theory that Earth cooled, forming mountain ranges.

Continental Drift Theory

Theory proposed by Alfred Wegener; a single large landmass named Pangaea breaks into smaller continents.

Driving Forces

Forces that push tectonic plates toward or away from one another.

Mantle Convection

Convection currents in the mantle drive plates away.

Slab Pull

Subducting slab sinks into the hot mantle.

Slab Suction

Two colliding plates are pulled down due to mantle convection currents.

Ridge Push

Oceanic ridge is formed; lithosphere is driven by gravity to pull apart.

Resisting Forces

Forces that act against the driving forces of plate tectonics.

Slab Resistance

Frictional force that stops plate movement in subduction zones.

Collisional Resistance

Frictional force that stops the subduction of a plate.

Transform Fault Resistance

Frictional force that stops plates moving past one another.

Drag Force

Frictional force that stops lithospheric plates through liquid.