Vocabulary#12 Moving Plates

Crust:Earth`s solid,rocky surface containing the continents and ocean floor.
S:For example when an earthquake occur the crust is moving.

Original horizontality:The idea that many kinds of rocks from in flat,horizontal layers.
S:The layers of sedimentary rock were once original horizontality.

Continental drift:The idea that a supercontinent split apart into pieces,the continents,which drifted in time to their present locations.
S:Pangaea was a supercontinent were there occur the continental drift.

Sea-floor spreading:The idea that new crust is forming at ridges in the sea floor,spreading apart the crust on either side of the ridges.
S:Scientist suggested a model to explain the huge crack called sea-floor spreading.

Magma:hot ,molten rock below Earth`s surface.
S:Magma flows through cracks,cools and hardens into new solid rock along the ridges.

Plate Tectonics:The idea that Earth`s surface is broken into plates that move.
S:Earth`s surface is broken in plates.

Mantle:Earth`s layers beneath the crust.
S:Plates move aroun in low portion of mantle.

Subduction:Where plates collide,the sliding of a denser ocean plate under another plate.
S:Subduction is a part of a cycle.