Unit 3: Plate Boundaries Lesson Objectives: To understand what occurs at different plate boundaries. Success Criteria: Create an annotated diagram of each plate boundary. Plate 1 Plate 2 Continental crust

THE WORLD’S MAIN PLATE BOUNDARIES Earthquake foci Destructive zones Constructive margin Movement of plates Collision zone Uncertain plate boundary key Plates A Adriatic B Aegean C Turkish D Juan de Fuca E Cocos 6 Rate of movement (cm per year)

Starter: Name the plate boundaries.

EARTHQUAKES ACTIVE VOLCANOES (shown as red dots) There is a relationship between plate boundaries and tectonic activity.

PLATE BOUNDARY Conservative (passive or transform) margins Destructive (convergent - subduction or collision) margins Constructive (spreading or divergent) margins Earthquakes are found at… Volcanoes are found at…

Two oceanic plates are moving away from each other and magma rises to the surface to create new crust. It forms mid-oceanic ridges such as the Mid Atlantic Ridge. (If this new material reaches above the ocean it forms land e.g. Iceland.) This activity leads to low magnitude earthquakes and also volcanoes. Click on the flash button below.

Iceland lies on the plate boundary between the North American and the Eurasian plates. The island has been created by divergent plate movement. The photo shows Thingvellir – to the right is the Eurasian plate and to the left is the North American plate Plates pulling apart

In oceanic areas: e.g. Mid Atlantic Ridge and Iceland Mid oceanic ridges and transform faults Shield volcanoes e.g. Surtsey Shallow focus earthquakes Surtsey Iceland A growing new volcanic island - Surtsey

In continental areas: Rift valleys

In continental areas: Volcanoes.

TYPES OF PLATE BOUNDARY 1 Constructive margins (spreading or divergent plates) Processes Two plates move apart from each other. New oceanic crust is formed, creating mid ocean ridges. Volcanic activity is common. Mid Atlantic Ridge (Europe is moving away from North America). 2 Destructive margin (subduction zone) Processes The oceanic crust moves towards the continental crust and sinks beneath it due to its greater density. Deep sea trenches and island arcs are formed. Volcanic activity is common. Example: Nazca sinks under the South American plate. Plate 1Plate 2 Lithosphere Asthenosphere Oceanic crust Mid-ocean ridge Rift valley Divergent margin Plate 1 Plate 2 Oceanic trench Continental crust Asthenosphere Oceanic crust Lithosphere Convergent margin (subduction)

When an oceanic plate moves towards a continental plate (subduction): Deep sea trenches Fold mountains -The Andes Explosive volcanoes Earthquakes (shallow, intermediate and deep) When 2 oceanic plates move toward each other the following are formed: oceanic trenches island arcs e.g. Japan explosive volcanoes earthquakes Nevado del Ruiz in Colombia

TYPES OF PLATE BOUNDARY (CONTINUED) 3 Collision zones Processes Two continental crusts collide. As neither can sink they are folded up into fold mountains. Example: The Indian plate collided with the Eurasian plate to form the Himalayas. 4 Conservative margins (passive margins or transform plates) Processes Two plates move sideways past each other but land is neither destroyed nor created. Example: San Andreas fault in California. Lithosphere Plate 1 Plate 2 Continental crust Asthenosphere Convergent margin (collision) Plate 1 Plate 2 Transform fault Lithosphere Asthenosphere Continental crust Transform fault margin

Plate 1 Plate 2 Continental crust At a collision margin two continental crusts collide. As neither can sink they are folded up into fold mountains. The Himalayas is an example of this, formed as India collided with the Eurasian plate. Shallow focus earthquakes are frequent along these boundaries

Task: Draw annotated diagrams of each plate boundary on a revision card. Include an example of each one. Plate 1 Plate 2 Continental crust Plate 1Plate 2 Lithosph ere Asthenosph ere Oceanic crust Mid-ocean ridge Rift valley Divergent margin Plate 1 Plate 2 Oceanic trench Continental crust Asthenosph ere Oceanic crust Lithosp here Convergent margin (subduction)

Unit 3: Plate Boundaries Lesson Objectives: To understand what occurs at different plate boundaries. Success Criteria: Create an annotated diagram of each plate boundary. Plate 1 Plate 2 Continental crust

Plenary In groups of four develop a group mime to show what happens at a Constructive or a destructive plate boundary.