Plate Tectonics

The Unifying Theory of Geology

Plate Tectonics

• lithosphere is broken up into tectonic plates

• seven major and many minor plates move on the asthenosphere’s convection currents

• These plates move in relation to one another

• Average Speed is __________ (we will fill in later)

Tectonic Plate Movements

• Divergence - away from each other

• Convergence - toward each other

• Transform motion - past each other

2-6,

Pangea

• The super continent that broke apart 190 million years ago to form the present continents.

http://www.wwnorton.com/college/geo/egeo/animations/ch2.htm#5

Wegner Continental Drift

Evidence of Plate Tectonics

http://wwnorton.com/college/geo/earth4/animations.aspx

• Fossils - same between continents formerly joined

• Ridges

• Volcanoes

• Earthquakes

• Trenches

• Sea Floor Spreading

• A ____________ of an organism that has been __________ in the earth's _________.

• Organism replaced by _________ to make a ________ _____

Fossil

part or track preservedcrust

minerals stone copy

• ________ and __________ at the surface of the earth resulting from underground __________ of _________ ______

Earthquake

shaking vibrationmovement tectonic plates

• A volcano is an _________ in the Earth's surface or crust, which allows ___, _______ _____, ____ and ______ to escape from deep below the surface.

• form ____________ over a period of time.

• Example:

Volcano

opening

hot molten rock ashgases

mountains

Challenge Deep , Mariana's Trench : Deepest point on the Earth Challenger Deep got its name from the British survey ship Challenger II, which pinpointed the deep water off the Marianas Islands in 1951. Then in 1960, the US Navy sent the Trieste (a submersible - a mini-submarine designed to go really deep) down into the depths of the Marianas trench to see just how far they would go. They touched bottom at 35,813 ft/10,915m. That means, while they were parked on the bottom in the bathyscaphe, there were almost seven miles/11km of water over their heads! If you cut Mount Everest off at sea level and put it on the ocean bottom in the Challenger Deep, there would still be over a mile of water over the top of it! The deepest measurement of the Challenger Deep currently available was taken by the Japanese and was found to be 35,838 feet.A plaque to commemorate the world record for the deepest dive to the bottom of the Mariana Trench in 1995

Trench•_________________- caused when an oceanic tectonic plate is pushed under another.

•Created by subduction

•Example:

Deepest Ocean

Mariana’s Trench

Ring of Fire

452 volcanoes, 81% of largest

Ridge

•_________________- caused by divergence

•As plate separates, the magma comes toward top of crust and cools as it mountains up

•Example:

Underwater Mts

Mid Atlantic Ridge

Sea Floor Spreading•New ________ _____ is created at mid ocean ridge from _________ ______

•Plate Movement - ____________

•Most important piece of _________ for _____ _______ theory

•Example:

http://www.wwnorton.com/college/geo/egeo/animations/ch2.htm#5

Sea Floor Spreading, Magnetic Reversal

Mid Atlantic Ridge

oceanic crustvolcanic activity

divergence

evidence plate tectonic

Subduction• Special type of convergence when one

tectonic plate moves _________ another

• Plate Movement - __________

• More _________ oceanic plates are pushed beneath the less dense ____________ plates

• Ex: ____________

The Process of Subduction

http://www.wwnorton.com/college/geo/egeo/animations/ch2.htm#5

beneath

dense

continental

Mariana Trench

convergence

• One tectonic plate moves ______ another

• Plate Movement - _____________

• creates lots of _____________

• Ex: ____________

Faults

past

transform motion

earthquakes

San Andreas Fault

India vs. Asia•Created by convergence - mountain building.

•Continental Plate vs. Continental plate

•Ex: Mount Everest (29,035 feet)

Mount Everest

Hot Spots

•pressure and heat builds up within a section of the asthenosphere

•Magma rises up through lithosphere to form a volcano and results in a new island.

•lithosphere moves over the hot spot to form a chain of islands

•40-50 around the globe

•Examples:

Hawaii, Galapagos

http://www.wwnorton.com/college/geo/egeo/animations/ch2.htm#5http://www.teachersdomain.org/resources/ess05/sci/ess/earthsys/hawaii/index.html

Plate movements

divergenceconvergence transform motion

RidgeEx: Mid Atlantic

FaultEx: San

Andreas

2 continental crust

continental & oceanic crust

mountainEx:

Mt. Everest

subduction

volcanoesEx: Mt. St Helens

trenchesEx: Mariana

Trench

RiftEx: AfricaRift Valley

oceanland