Unit 3 Plate Boundaries Lesson Objectives To understand

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

THE WORLD’S MAIN PLATE BOUNDARIES 2 5 5 3 2 5 17 10 3 2 5 7 18 1 7 4 18 3 1 2 key Plates Earthquake foci Constructive margin Collision zone Destructive zones Movement of plates Uncertain plate boundary A Adriatic B Aegean C Turkish D Juan de Fuca E Cocos 6 Rate of movement (cm per year) 2

Starter: Name the plate boundaries.

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

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

Landforms at constructive boundaries 1 In oceanic areas: e. g. Mid Atlantic Ridge and Iceland • Mid oceanic ridges and transform faults • Shield volcanoes e. g. Surtsey • Shallow focus earthquakes Iceland A growing new volcanic island - Surtsey

Landforms at constructive boundaries 2 In continental areas: • Rift valleys

Landforms at constructive boundaries 3 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). Divergent margin Plate 1 Oceanic crust 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. Convergent margin (subduction) Plate 1 Plate 2 Mid-ocean ridge Rift valley Asthenosphere Continental crust Oceanic trench Oceanic crust Lit ho Lithosphere sp Asthenosphere Plate 2 he re

Landforms at destructive boundaries 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: Nevado del Ruiz in Colombia • oceanic trenches • island arcs e. g. Japan • explosive volcanoes • earthquakes

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. Convergent margin (collision) 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. Transform fault margin Plate 1 Plate 2 Transform fault Continental crust Lithosphere Asthenosphere 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. Plate 1 Plate 2 Continental crust 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 Divergent margin Oceanic crust Plate 1 Rift valley Plate 2 Mid-ocean ridge Lithosph ere Asthenosph ere Oceanic crust Convergent margin Plate 1 Plate 2 (subduction) Continental Oceanic trench Lit he hosp Asthenosph re ere crust

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