Plate Tectonics 7 th Grade Science
Area of Focus: Plate Tectonics Copyright © 2010 Ryan P. Murphy
Plate tectonics: The earth’s crust and upper mantle are broken into sections called plates. – These plates float on the mantle like rafts (moving very slowly) Copyright © 2010 Ryan P. Murphy
Plate tectonics: The earth’s crust and upper mantle are broken into sections called plates. – These plates float on the mantle like rafts (moving very slowly) Copyright © 2010 Ryan P. Murphy
Continental Drift: The gradual movement of the continents across the earth. Copyright © 2010 Ryan P. Murphy
The speed at which the plates move is about the speed at which your fingernails grow. Copyright © 2010 Ryan P. Murphy
Video! How did the continents form?
In 1915, The German geologist Alfred Wegener ( ) proposed continental drift. Copyright © 2010 Ryan P. Murphy
In 1915, The German geologist Alfred Wegener ( ) proposed continental drift. Copyright © 2010 Ryan P. Murphy “I say.” “Africa and South America fit strangely like two puzzle pieces.”
In 1915, The German geologist Alfred Wegener ( ) proposed continental drift. Not accepted until the 1950’s! Copyright © 2010 Ryan P. Murphy
Evidence for continental drift. – - Copyright © 2010 Ryan P. Murphy
The shapes match. Copyright © 2010 Ryan P. Murphy
Same fossils found on different continents – These are the pictures on the puzzle pieces. Copyright © 2010 Ryan P. Murphy
Same fossils found on different continents – These are the pictures on the puzzle pieces. Copyright © 2010 Ryan P. Murphy
The Same rock structures on different continents Copyright © 2010 Ryan P. Murphy
What is this a fossil of? – Where would you expect to find a specimen like this on the planet? Copyright © 2010 Ryan P. Murphy
Answer! This is a fossilized tropical plant found on Antarctica. Copyright © 2010 Ryan P. Murphy
Answer! This is a fossilized tropical plant found on Antarctica. – Remember, the continents have moved and Antarctica use to be in a warmer climate. Copyright © 2010 Ryan P. Murphy
Fossils of plants and animals in Antarctica Copyright © 2010 Ryan P. Murphy
Behold the Supercontinent! Pangea ? Copyright © 2010 Ryan P. Murphy
Behold the Supercontinent! Pangea Copyright © 2010 Ryan P. Murphy
Pangea: The “Super Continent” – All of the plates were once together. Copyright © 2010 Ryan P. Murphy
Pangea: The “Super Continent” – All of the plates were once together. Copyright © 2010 Ryan P. Murphy
– Gondwondaland and Laurasia were two mega continents after Pangea. Copyright © 2010 Ryan P. Murphy
Current Day + or – 4mm
What causes continental drift and plate tectonics? Copyright © 2010 Ryan P. Murphy
Answer! – Convection currents (Remember heat rises) move the plates Copyright © 2010 Ryan P. Murphy
Answer! – Convection currents (Remember heat rises) move the plates Copyright © 2010 Ryan P. Murphy
Answer! – Convection currents (Remember heat rises) move the plates Copyright © 2010 Ryan P. Murphy
Answer! – Convection currents (Remember heat rises) move the plates Copyright © 2010 Ryan P. Murphy
Video! Plate Tectonics
Layers of the earth Copyright © 2010 Ryan P. Murphy
Layers of the earth Copyright © 2010 Ryan P. Murphy
Layers of the earth Copyright © 2010 Ryan P. Murphy
Layers of the earth Copyright © 2010 Ryan P. Murphy
Layers of the earth Copyright © 2010 Ryan P. Murphy
Layers of the earth Copyright © 2010 Ryan P. Murphy
Earth’s layers formed early in it’s long history. Copyright © 2010 Ryan P. Murphy
Earth’s layers formed early in it’s long history. – (Archean Eon) Gravity pulled heavy elements toward the middle. Copyright © 2010 Ryan P. Murphy
Inner Core: Solid Iron and Nickel (Dense). Copyright © 2010 Ryan P. Murphy
Hot and Dense Less Hot and Dense Copyright © 2010 Ryan P. Murphy
The spinning inner cores of solid and liquid Iron creates a giant electromagnetic field. Copyright © 2010 Ryan P. Murphy
Outer Core: Liquid Iron and Nickel Copyright © 2010 Ryan P. Murphy
Mantle: Composed of Magnesium Silicates, Iron, Calcium Copyright © 2010 Ryan P. Murphy
Mantle: Composed of Magnesium Silicates, Iron, Calcium - Outer Mantle (Asthenosphere) Copyright © 2010 Ryan P. Murphy
Mantle: Composed of Magnesium Silicates, Iron, Calcium - Outer Mantle (Asthenosphere) - Lithosphere (Crust) Copyright © 2010 Ryan P. Murphy
Review! Heat from the earth rises and run along plates causing them to move. Copyright © 2010 Ryan P. Murphy
New Area of Focus: Earth’s Plate Boundaries. Copyright © 2010 Ryan P. Murphy
Two types of Crust – - Copyright © 2010 Ryan P. Murphy
Oceanic Crust: More dense so it sinks more (Basalts). Copyright © 2010 Ryan P. Murphy
Continental Crust: Less Dense so it floats higher (Granites) Copyright © 2010 Ryan P. Murphy
Which plates below are ocean plates?
Answer! Nazca Plate.
Answer! Pacific Plate
Answer!
Activity! Using Google Earth to look at divergent ocean plate boundaries on the sea floor. –
Divergent Boundaries: Crust is created as two or more plates pull away from each other. Copyright © 2010 Ryan P. Murphy
Newer
Older
Newer Older
Newer Older 4 miles thick
Convergent Boundaries: Crust is destroyed and recycled back into the interior of the earth. – One plate dives under another. Copyright © 2010 Ryan P. Murphy
Convergent Boundaries: Crust is destroyed and recycled back into the interior of the earth. – One plate dives under another. Copyright © 2010 Ryan P. Murphy
Ocean vs. Continent (Subduction zone) Copyright © 2010 Ryan P. Murphy
Ocean vs. Continent (Subduction zone) – The oceanic plate is forced below the continental plate. Copyright © 2010 Ryan P. Murphy
What is the “Ring of Fire”? Copyright © 2010 Ryan P. Murphy
What is the “Ring of Fire”? Copyright © 2010 Ryan P. Murphy
Ring of Fire: A zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean. Copyright © 2010 Ryan P. Murphy
Ring of Fire: A zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean. Copyright © 2010 Ryan P. Murphy
Ring of Fire: A zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean. Copyright © 2010 Ryan P. Murphy
Many tropical Islands like this are created by ocean plates and volcanism. Copyright © 2010 Ryan P. Murphy
Ocean Plate
Copyright © 2010 Ryan P. Murphy Ocean Plate
Copyright © 2010 Ryan P. Murphy Ocean Plate Volcanic Arch Island Chain / Archipelago
Video Link! New volcanic island forming – E E
Transform-Fault Boundaries: Where two plates are sliding horizontally past one another. Copyright © 2010 Ryan P. Murphy
Coastal California and the Baja Peninsula will become an Island.
Continental Convergence: (Mountain Building). Copyright © 2010 Ryan P. Murphy
The Swiss Alps is an example of mountains that form when continents collide. – The African Plate is colliding with the European Plate
The Swiss Alps is an example of mountains that form when continents collide. – The African Plate is colliding with the Eurasian plate/
Indian Continental Plate is crashing into Asian Plate causing the mountains to form. – They are still growing. Copyright © 2010 Ryan P. Murphy
Himalayas: Tallest Mountains on Earth.
Continent Divergence (Moving apart). Copyright © 2010 Ryan P. Murphy
Ocean vs. Ocean Convergence Copyright © 2010 Ryan P. Murphy
Antilles in Caribbean
Aleutian Islands Alaska
Indonesia – Every triangle is a volcano