Plate TectonicsPlate Tectonics

Earth’s LayersEarth’s LayersThe Earth's rocky outer crust solidified billions of years ago, soon after the Earth formed.

This crust is not a solid shell; it is broken up into huge, thick plates that drift atop the soft, underlying mantle.

The CrustThe Crust

Outermost layerOutermost layer 5 – 100 km thick5 – 100 km thick Made of Oxygen, Silicon, Made of Oxygen, Silicon,

AluminumAluminum

The MantleThe Mantle Layer of Earth Layer of Earth

between the between the crust and the crust and the corecore

Contains most of Contains most of the Earth’s massthe Earth’s mass

Has more Has more magnesium and magnesium and less aluminum less aluminum and silicon than and silicon than the crustthe crust

Is denser than Is denser than the crustthe crust

The CoreThe Core

Below the mantle Below the mantle and to the center and to the center of the Earthof the Earth

Believed to be Believed to be mostly Iron, mostly Iron, smaller amounts smaller amounts of Nickel, almost of Nickel, almost no Oxygen, no Oxygen, Silicon, Aluminum, Silicon, Aluminum, or Magnesiumor Magnesium

Tectonic PlatesTectonic Plates

Plate TectonicsPlate Tectonics

Greek – “tektonikos” of a builderGreek – “tektonikos” of a builder Pieces of the lithosphere that move Pieces of the lithosphere that move

aroundaround Each plate has a nameEach plate has a name Fit together like jigsaw puzzlesFit together like jigsaw puzzles Float on top of mantle similar to ice Float on top of mantle similar to ice

cubes in a bowl of watercubes in a bowl of water

Continental DriftContinental Drift

http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml

Alfred Wegener 1900’sContinents were once a single land mass that drifted apart.

Fossils of the same plants and animals are found on different continents

Called this supercontinent Pangea, Greek for “all Earth”

245 Million years ago

Split again – Laurasia & Gondwana 180 million years ago

Evidence of PangeaEvidence of Pangea

Sea Floor SpreadingSea Floor Spreading

Sea Floor SpreadingSea Floor Spreading

Mid Ocean Ridges – underwater Mid Ocean Ridges – underwater mountain chains that run through mountain chains that run through the Earth’s Basinsthe Earth’s Basins

Magma rises to the surface and Magma rises to the surface and solidifies and new crust formssolidifies and new crust forms

Older Crust is pushedOlder Crust is pushedfarther away from the ridgefarther away from the ridge

How Plates MoveHow Plates Move

http://pubs.usgs.gov/gip/dynamic/unanswered.html

Different Types of BoundariesDifferent Types of Boundaries

http://pubs.usgs.gov/gip/dynamic/understanding.html

Divergent Boundary – Divergent Boundary – Arabian and African PlatesArabian and African Plates

Divergent Boundary – Divergent Boundary – IcelandIceland

http://pubs.usgs.gov/gip/dynamic/understanding.html

Divergent Boundary - OceanicDivergent Boundary - Oceanic

http://www.geology.com

Divergent Boundary - ContinentalDivergent Boundary - Continental

http://www.geology.com

Convergent Boundary – Indian and Eurasian Convergent Boundary – Indian and Eurasian PlatesPlates

Convergent Boundary – Oceanic & ContinentalConvergent Boundary – Oceanic & Continental

http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Convergent Boundary – Oceanic & OceanicConvergent Boundary – Oceanic & Oceanic

http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Convergent Boundaries - ContinentalConvergent Boundaries - Continental

http://pubs.usgs.gov/gip/dynamic/understanding.html & http://www.geology.com

Transform Boundary – San Andreas FaultTransform Boundary – San Andreas Fault

www.geology.com

ReviewReview

Name the 3 main layers of the EarthName the 3 main layers of the Earth What is a tectonic plate?What is a tectonic plate? What was Pangea?What was Pangea? What is Sea-Floor spreading?What is Sea-Floor spreading? Name the three different types of Name the three different types of

plate boundaries and one location on plate boundaries and one location on Earth for each oneEarth for each one