Plate Tectonics 7 th Grade Science. Area of Focus: Plate Tectonics Copyright © 2010 Ryan P. Murphy

Plate Tectonics 7th Grade Science

• Area of Focus: Plate Tectonics

• 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)

• 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)

• Continental Drift: The gradual movement of the continents across the earth.

• The speed at which the plates move is about the speed at which your fingernails grow.

• Video! How did the continents form?

• In 1915, The German geologist Alfred Wegener (1880-1930) proposed continental drift.

“I say.” “Africa and South America fit strangely like two puzzle pieces.”

• In 1915, The German geologist Alfred Wegener (1880-1930) proposed continental drift. Not accepted until the 1950’s!

• Evidence for continental drift.– -– -– -– - – -

• The shapes match.

• Same fossils found on different continents– These are the pictures on the puzzle pieces.

• The Same rock structures on different continents

• What is this a fossil of?– Where would you expect to find a specimen like

this on the planet?

• Answer! This is a fossilized tropical plant found on Antarctica.

• Answer! This is a fossilized tropical plant found on Antarctica.– Remember, the continents have moved and

Antarctica use to be in a warmer climate.

• Fossils of plants and animals in Antarctica

• Behold the Supercontinent! Pangea

• Pangea: The “Super Continent” – All of the plates were once together.

– Gondwondaland and Laurasia were two mega continents after Pangea.

• Current Day + or – 4mm

• What causes continental drift and plate tectonics?

• Answer! – Convection currents (Remember heat rises) move

the plates

Video! Plate Tectonics

• Layers of the earth

• Earth’s layers formed early in it’s long history.

• Earth’s layers formed early in it’s long history.– (Archean Eon) Gravity pulled heavy elements

toward the middle.

• Inner Core: Solid Iron and Nickel (Dense).

Hot and Dense

Less Hot and Dense

• The spinning inner cores of solid and liquid Iron creates a giant electromagnetic field.

• Outer Core: Liquid Iron and Nickel

• Mantle: Composed of Magnesium Silicates, Iron, Calcium

- Outer Mantle (Asthenosphere)

- Outer Mantle (Asthenosphere)- Lithosphere (Crust)

• Review! Heat from the earth rises and run along plates causing them to move.

• New Area of Focus: Earth’s Plate Boundaries.

• Two types of Crust– -– -

• Oceanic Crust: More dense so it sinks more (Basalts).

• Continental Crust: Less Dense so it floats higher (Granites)

• 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.– http://www.google.com/earth/index.html

• Divergent Boundaries: Crust is created as two or more plates pull away from each other.

Newer Newer

Newer NewerOlder Older

4 miles thick

• Convergent Boundaries: Crust is destroyed and recycled back into the interior of the earth.– One plate dives under another.

• Ocean vs. Continent (Subduction zone)

• Ocean vs. Continent (Subduction zone)– The oceanic plate is forced below the continental

plate.

• What is the “Ring of Fire”?

• Ring of Fire: A zone of frequent earthquakes and volcanic eruptions that encircles the basin of the Pacific Ocean.

• Many tropical Islands like this are created by ocean plates and volcanism.

Ocean Plate

Volcanic Arch Island Chain / Archipelago

• Video Link! New volcanic island forming– http://www.youtube.com/watch?v=kwETZSARMg

• Transform-Fault Boundaries: Where two plates are sliding horizontally past one another.

• Coastal California and the Baja Peninsula will become an Island.

• Continental Convergence: (Mountain Building).

• 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.

• Himalayas: Tallest Mountains on Earth.

• Continent Divergence (Moving apart).

• Ocean vs. Ocean Convergence

• Antilles in Caribbean

• Aleutian Islands Alaska

• Indonesia – Every triangle is a volcano

Plate Tectonics 7 th Grade Science. Area of Focus: Plate Tectonics Copyright © 2010 Ryan P. Murphy

Documents

Plate Tectonics Continental Drift Theory Theory of Plate Tectonics Plate Boundaries

Plate tectonics : chapter 9.3 & 9.4 Plate tectonics : chapter 9.3 & 9.4

Plate Tectonics Plate Tectonics Chapter 17.1. Plate Tectonics Overview Historical Development Continental Drift and Paleomagnetism

Plate Tectonics EQ: What is the theory of plate tectonics?

Theory of Plate Tectonics Plate Tectonics Plate Boundaries Causes of Plate Tectonics

Plate Tectonics - UNLV Geosciencegeoscience.unlv.edu/Terry_GEOL101_Powerpoint/Plate Tectonics.pdf · Plate Tectonics Plate tectonics is responsible for: Volcanoes ... divergent margins,

Investigation 11A Plate Tectonics 11A Plate Tectonics Ea… · Investigation 11A Plate Tectonics 11A Plate Tectonics ... this key for your earthquakes, ... Explain your answer. b

Chapter Plate Tectonics - jkaser.com 9 Plate... · Chapter Plate Tectonics. ... 9.2 Plate Tectonics ... 9.2 Plate Tectonics Divergent boundaries (also called spreading centers) are

Plate Tectonics Mrs. Anton. Continental Drift Caused By Plate Tectonics

Plate tectonics alaskan tectonics

Plate Tectonics - Brock Universityspartan.ac.brocku.ca/.../1F90/Fall-Winter2009-10/PDF/PlateTectonics… · Plate Boundaries Driving Mechanisms of Plate Tectonics Plate Tectonics

Plate Tectonics Causes of Plate Tectonics Plate Boundaries

Early plate tectonics versus single-plate tectonics on ...step.ipgp.fr/images/c/c1/Alire3.pdf · Early plate tectonics versus single-plate tectonics on Mars: Evidence from magnetic

Plate Tectonics Review Misc. Plate Tectonics Plate Evidence Earth's Interior Geologic Events Plate Boundaries

Plate Tectonics Plate Boundaries Causes of Plate Tectonics

Tectonics: Plate Tectonics

Tectonics: Plate tectonics Introduction

Plate Tectonics Activity.??? What is plate tectonics?

Plate Tectonics. Major Divisions of Earth Plate Tectonics

CONTINENTAL DRIFT SEAFLOOR SPREADING THEORY OF PLATE TECTONICS Plate Tectonics