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Plate Tectonics. Tectonic Plates are…. Pieces of the lithosphere that move around on top of the asthenosphere are called tectonic plates. Tectonic plates consist of the crust and the rigid, outermost part of the mantle.

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Tectonic plates are
Tectonic Plates are…

  • Pieces of the lithosphere that move around on top of the asthenosphere are called tectonic plates.

  • Tectonic plates consist of the crust and the rigid, outermost part of the mantle.

    • Remember! The plates are a part of the lithosphere so they are made of the same thing!


A giant jigsaw puzzle
A Giant Jigsaw Puzzle

  • Each tectonic plate fits together with the tectonic plates that surround it.

  • The lithosphere is like a jigsaw puzzle. The tectonic plates are like the pieces of the puzzle.



  • Tectonic plates “float” on the fit together like the puzzle just mentioned.asthenosphere.

    • Remember? Like ice on water!!

  • The plates cover the surface of the asthenosphere, and they touch one another and move around.


  • Continental drift fit together like the puzzle just mentioned.is the hypothesis that states that continents once formed a single landmass, broke up, and drifted to their present locations.

  • Scientist Alfred Wegenerdeveloped this continental drifthypothesis in the early 1900s.

    • People were NOT happy about it!




Pangaea
Pangaea? fossils of the same species were found on continents separated by ocean.

  • Wegener theorized that all of the present continents were once joined in a single, huge continent he called Pangaea. Pangaea existed about 245 million years ago!

  • Pangaea is Greek

    for “all Earth”


Taking a look at Pangaea over the years… fossils of the same species were found on continents separated by ocean.

http://www.wwnorton.com/college/geo/egeo/flash/2_1.swf


Sea floor spreading
Sea-Floor Spreading fossils of the same species were found on continents separated by ocean.

  • Evidence to support the continental drift hypothesis comes from sea-floor spreading.

  • Sea-floor spreading is the process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies.


Mid ocean ridges sea floor spreading
Mid-Ocean Ridges & Sea-Floor Spreading fossils of the same species were found on continents separated by ocean.

  • Mid-ocean ridges are underwater mountain chains that run through Earth’s ocean basins.

  • This is where sea-floor spreading takes place!

http://www.wwnorton.com/college/geo/egeo/flash/2_5.swf-An animation depicting sea-floor spreading of the Mid-Atlantic Ridge.


Evidence for sea floor spreading magnetic reversals
Evidence for Sea-Floor Spreading fossils of the same species were found on continents separated by ocean. Magnetic Reversals

  • Some of the most important evidence of sea-floor spreading comes from magnetic reversals recorded in the ocean floor.

  • Throughout Earth’s history, the north and south magnetic poles have changed places many times.


Cont. fossils of the same species were found on continents separated by ocean.

  • Molten rock at the mid-ocean ridge contains tiny grains of magnetic minerals that act like compasses.

  • These minerals align with the magnetic field of the Earth. When the molten rock cools, the record of these tiny compasses remains in the rock.


Cont. fossils of the same species were found on continents separated by ocean.

  • When the Earth’s magnetic field reverses, the magnetic mineral grains align in the opposite direction. The new rock records the direction of the Earth’s magnetic field.

  • As the sea floor spreads away from a mid-ocean ridge, it carries with it a record of these magnetic reversals.


Plate tectonics boundaries

Plate Tectonics & Boundaries fossils of the same species were found on continents separated by ocean.


Tectonic plate boundaries
Tectonic Plate Boundaries fossils of the same species were found on continents separated by ocean.

  • As scientists’ understanding of mid-ocean ridges and magnetic reversals grew, a theory was formed to explain how tectonic plates move.

  • Plate tectonics is the theory that explains how large pieces of the Earth’s outermost layer, called tectonic plates, move and change shape.


  • A fossils of the same species were found on continents separated by ocean.boundary is a place where tectonic plates touch. All tectonic plates share boundaries with other tectonic plates.

  • The type of boundary depends on how the tectonic plates move relative to one another.



  • When two tectonic plates collide fossils of the same species were found on continents separated by ocean., the boundary between them is a convergent boundary.

  • What happens at convergent boundaries depends on the kind of crust at the leading edge of each tectonic plate.

Draw these arrows in the empty box to the right of the notes.


The 3 types of convergent boundaries are: fossils of the same species were found on continents separated by ocean.



Draw these arrows in the empty box to the right of the notes.



Draw these arrows in the empty box to the right of the notes.



  • Remember! groove along the San Andreas Fault” that slices through the Carrizo Plain, about 100 miles north of L.A.

    • Convection is the movement within the mantle that is responsible for plate motion.


Tectonic plate motion
Tectonic Plate Motion… groove along the San Andreas Fault” that slices through the Carrizo Plain, about 100 miles north of L.A.

  • Tectonic plate movements are so slow and gradual that you can’t see or feel them. The movement is measured in CENTIMETERS per year!



The end create level 2 and 3 questions for your notes
THE END - Create level 2 and 3 questions for your notes! groove along the San Andreas Fault” that slices through the Carrizo Plain, about 100 miles north of L.A.

  • Compare

  • Contrast

  • Classify

  • Sort

  • Distinguish

  • Explain Why

  • Infer

  • Analyze

  • Synthesize

  • Make analogies

  • Evaluate

  • Generalize

  • Imagine

  • Judge

  • Predict

  • Speculate

  • Apply a…

  • Forecast

  • Pretend

  • Create

Level 2

Level 3


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