Our Earth Not a solid ball of rock Composed of distinct layers Three main layers based on
composition: Crust Mantle Core
The lightest materials make up the outer layers.
The densest materials make up the inner layers.
Let’s Review …
Outermost layer of the Earth. Two types of crust
Continental Less dense than oceanic crust. Contains the Earth’s continents.
Oceanic Found primarily under the ocean. Most dense type of crust.
Crust
The innermost part of the earth. Very dense. Composed of iron and nickel. About the size of the planet Mars.
Core
Outermost rigid layer. Made of 2 parts: the crust and rigid
upper part of the mantle. Divided into pieces called tectonic plates.
Lithosphere
There are approximately 30 plates on the Earth’s surface.
The plates move on a layer of rock that is so hot it flows, even though it remains solid.
The plates are moving at speeds up to 10 cm per year.
Plate Tectonics
Plate Boundaries
Divergent Boundary – move _____
Convergent Boundary – move _____________
Transform Fault Boundary – move ___________________
apart
together (collide)
sideways past each other
Places where two plates move apart or diverge.
Divergent boundaries of two continental plates creates a ________. Example: Great Rift Valley of Africa
Divergent boundaries of two oceanic plates creates a _____. Example: Mid-Atlantic Ridge
Divergent Boundary
rift valley
ridge (sea-floor spreading)
Places where two plates come together, or converge.
Convergent boundaries of two continental plates creates _________. Example: Himalaya Mountains
Convergent boundaries between a continental plate and an oceanic plate forms a __________________ and a ______. This process is called ___________. Example: Coast of Chile
Convergent Boundary
mountains
trenchsubduction
volcanic mountain range
Convergent boundaries of two oceanic plates creates ________ and a _____. Example: Islands of Japan
Ocean – Ocean Plates
island arc
trench
Places where two plates slip past each other, moving in opposite directions. Example: San Andreas Fault in California
Transform Boundary
Places where plates move apart are called ________ boundaries.
When continental plates diverge a ________ is formed.
When two oceanic plates converge a ___________________ is formed.
The force moving the plates is _________ . ________ is the process where a denser
______ plate slides under a ________ plate.
Let’s Review…
divergent
rift valley
an island arc and a trench convectio
nSubductionocean
continent