Year 9 Science Earth's Crust and Plate Tectonics

inner core

really hot solid sphere of iron and nickel

Mantle

thickest layer, consists of molten rock

Crust

the outside layer, is the thinnest, made of mostly solid rock

oceanic crust

thinner solid outer layer

continental crust

thicker solid outer layer

Lithosphere

the rigid outer part of the earth, consisting of the crust and upper mantle.

tectonic plates

the two sub-layers of the earth's crust that move, float, and sometimes fracture and whose interaction causes continental drift, earthquakes, volcanoes, mountains, and oceanic trenches.

The border between two tectonic plates is called

boundary

Plates that push together

convergent

Plates moving apart

divergent

Sliding plates

transform

Continental plate collides with an oceanic plate.

The denser oceanic plate is pulled under the continental plate and creates a trench.

subduction zone

When a plate is forced under another, or subducted

when two oceanic plates collide.

The older plate is forced under the younger one

Island arcs what are they

They are small volcanic islands

What event is often associated with subduction zones and the collision of plates

earthquakes

what is created when two continental plates collide

they create mountains and mountain ranges.

what happens at divergent boundaries found in the middle of the ocean.

The oceanic plates split apart and magma oozes out and then hardens

what happens when two continental plates diverge.

A valley-like rift appears