what are the different types of plate boundaries? · fault east pacific rise transform fault...
TRANSCRIPT
What are the different types of plate boundaries?
Continental Drift• The continents drift across our planet’s surface on great plates of crust that float
on the hot underlying mantle
• These plates often slide along the boundary of other plates, pulling apart or pushing each other
What does the inside of Earth look like?How does this move the plates?
Plates• The lithosphere is composed of the crust and upper mantle.
• It is divided into massive sections known as plates.
• The plates float and move on the viscous asthenosphere.
Convection Currents• The material deepest in the mantle gets heated to very high
temperatures and then rises to the surface of the mantle.
• When the material reaches the top, it cools and becomes dense then sinks.
• Because of this the mantle is slowly churning creating a convection current.
Tectonic plate
Collision between
two continents
Oceanic tectonic
plate
Spreading
center Oceanic tectonic
plateOcean trench
Plate movement Plate movement
Continental
crust
Subduction
zone
Oceanic
crust
Oceanic
crust
Continental
crust
Mantle
Inner
core
Hot outer
core
Two plates movetowards each other.One is subductedback into the mantleon falling convectioncurrent.
Mantleconvectioncell
Hot materialrisingthroughthe mantle
Material coolsas it reachesthe outer mantle
Cold densematerial fallsback throughmantle
EURASIAN PLATE
CHINA
SUBPLATE PHILIPPINEPLATE
INDIAN-AUSTRLIAN PLATE
PACIFICPLATE
JUAN DEFUCA PLATE
COCOSPLATE
CARIBBEANPLATE
NORTHAMERICAN
PLATE
SOUTHAMERICAN
PLATE
EURASIANPLATE
ANATOLIANPLATE
ARABIANPLATE
AFRICANPLATE
SOMALIANSUBPLATE
Carlsberg
Ridge
Southwest IndianOcean Ridge
ANTARCTIC PLATE
Transformfault
East PacificRise
Transformfault
Mid-IndianOceanRidge
Southeast IndianOcean Ridge
Mid-AtlanticOceanRidge
ReykjanesRidge
Transformfault
Divergent ( ) andtransform fault ( )boundaries
Convergentplate boundaries
Plate motionat convergentplate boundaries
Plate motionat divergentplate boundaries
When continents collide!
• As these plates move around sometimes they bump into each other causing earthquakes and sometimes volcanoes.
• Where the edges of different plates meet are plate boundaries.
• There are different types of plate boundaries: convergent, divergent, and transform.
Convergent Boundaries2 plates collide together
• When one plate moves under another during a collision, we call it subduction.
• The plate that goes under gets pushed deep into the Earth and gets heated and changed into magma.
• Sometimes the magma escapes through weak spots in the crust to erupt through a volcano.
Mt. Shasta
1) Continent to Ocean Subduction
The denser ocean plate subducts under the less dense continental plate• This creates volcanoes on the continent plate.• Ocean plate goes under• Water squeezed out• Super heats the rock and melts it• Melted rock rises up and goes through the crust• This forms a volcano
2) Continent to continent• When two continents collide they deform crustal rocks by folding
and faulting them.
• Huge mountain ranges form
3) Ocean plate to ocean plate
• What do you think happens when two dense ocean plates come together with no land on top?
One plate will go under the other plate and melt just like when the ocean plate goes under a continental plate
This also makes volcanoes, but slightly different
They create new land called Island arcs or land bridges.
Lithosphere
Trench
Volcanic island arc
Asthenosphere
Risingmagma
Subductionzone
Trench and volcanic island arc at a convergent
plate boundary
When to ocean plates collide they form an island arc. This also creates new land and land bridges
Land BridgesAllow species to invade new areaThey may result from plate tectonic activity or the lowering of seawater Examples: North America and AsiaEngland and Europe now separated by the English Channel
Divergent Plate Boundaries
Include both rift valley and oceanic ridge.
Divergent boundaries
• Sometimes two plates are moving away from each other, creating a divergent boundary.
• Melted rock from the mantle can seep to the surface at these boundaries and form new crust.
• Most divergent boundaries are in the ocean and build undersea mountain ranges called mid-ocean ridges.
Lithosphere
Asthenosphere
1) Oceanic ridge at a divergent plate boundary
Forms a ridge under waterThe 2 plates push a way from each otherIceland was formed because of this process
Hydrothermal vents create unique living experiences.
2) On land divergent boundaries create rift valleys• create volcanoes and earthquakes • push the land apart• Eventually forming a new ocean
Transform boundaries
• Transform boundaries form where two plates slide past each other.
• The sliding causes rock along the boundary to grind against each other causing earthquakes.
• Example: San Andreas fault
Liquefaction ofrecent sedimentscauses buildingsto sink
Landslides mayoccur onhilly ground
Shockwaves
Epicenter
Focus
Two adjoining platesmove laterally alongthe fault line
Earth movementscause flooding inlow-lying areas
extinctvolcanoes
magmareservoir
centralvent
magmaconduit
Solidlithosphere
Upwellingmagma Partially molten
asthenosphere
Hot Spots
Famous hot spots.
