1.4 What are the major landforms found at the plate boundaries?

1. 1.4 What are the major landforms found at the plate boundaries?

2. What landforms does internal force form at destructive plate boundaries? How are destructive plate boundaries formed? Use these words to help you! Magma currents converge and create compressional force. They drag the plates towards each other. Magma currents Converge Compressional force Please click above for animation Towards each other

3. What landforms does internal force form at destructive plate boundaries? What will happen when two plates collide? Volcanic eruption Continental crust Plate Oceanic crust Uppermost part of the mantle Plate Uppermost part of the mantle The denser or heavier plate slides or subducts below the other plate Asthenosphere Compressional force Subduction zone

4. What landforms does internal force form at destructive plate boundaries? Where is the destructive plate boundary? At A, B or C? How do you know?

5. What landforms does internal force form at destructive plate boundaries? Destructive plate boundaries can be found at two major belts. How do you describe the distribution of the two belts? Alpine-Himalayan Belt Circum-Pacific Belt They run on land or along land margins.

6. What landforms are created where plates collide? The types of landforms depend on the nature of the colliding crusts. Convergence of magma currents Compressional force Continent-continent collision: Two plates with continental crusts at their edges collide Ocean-ocean collision: Two plates with oceanic crusts at their edges collide Ocean-continent collision: A plate with continental crust and a plate with oceanic crust at their edges collide

7. What landforms does internal force form at constructive plate boundaries? Where is the constructive plate boundary? At A, B or C? How do you know?

8. Constructive plate boundaries can be found in four zones. What landforms does internal force form at constructive plate boundaries? Mid-Atlantic zone Mid-Indian zone South-east Pacific zone Antarctic zone

9. What landforms does internal force form at constructive plate boundaries? How are constructive plate boundaries formed? Use these words to help you! Magma currents diverge and create tensional force. They drag the plates apart. Magma currents Diverge Tensional force Please click above for animation Drag apart

10. What landforms are created where plates diverge? Magma currents diverge Tensional force Mid-oceanic ridges Rift valleys Submarine volcanoes and volcanic islands

11. What will happen when magma currents continue to diverge? Old oceanic ridges and submarine volcanoes are carried away from the zone of rising magma. The ocean floor is ( shrinking / expanding ) at the zone of divergence. It is called ___________________. sea-floor spreading Will the sea floor spread without limit? Why?

12. What landforms does internal force form at conservative plate boundaries? Conservative plate boundaries are found where two plates ______ ______ each other. San Andreas Fault North American Plate slide past Lateral force causes _________. San Andreas Fault faulting San Andreas The _____________ Fault is located at the conservative plate boundary in California, the USA. Pacific Plate (Credit: Tom Bean/Corbis)

15. 1 Continent-continent collision What happens when two plates with continental crusts at their edge collide? Eruasian Plate Indo-Australian Plate

16. 1 Continent-continent collision Please click above for animation

17. The magma currents brought the Indian subcontinent northwards and towards the Asian continent. The ________ crust of the Indo-Australian Plate subducted beneath the Eurasian Plate at the destructive plate boundary between them. Sediment was deposited in the coastal waters. Due to the weight of the overlying sediment, the layers of sediment were compacted into sedimentary rock. 1 Continent-continent collision oceanic

18. When the two landmasses were getting closer together, neither of the continental crusts of both plates could subduct since both of them are thick and light. The sea between the plates reduced in size and finally disappeared. Under great compressional force, the sedimentary rock folded up and rose up to form ___________________, calledthe Himalayas. 1 Continent-continent collision fold mountains

19. 2 Ocean-ocean collision When the North American Plate collides with the Pacific Plate, do they create fold mountains? North American Plate Pacific Plate

20. 2 Ocean-ocean collision How does the denser Pacific Plate move when the magma currents converge? During the subduction, what will happen inside the asthenophere and on the earth’s surface? The submarine volcanoes appear parallel to the Aleutian Trench. Some of them may rise above the sea level to become ________________. They finally develop into a chain of __________________. volcanic islands volcanic island arc Pacific Ocean Magma rises through cracks Sedimentary rock is folded up Volcanic island arc (Aleutian Islands) Ocean trench (Aleutian Trench) Sediment and sedimentary rock Pacific Plate North American Plate Subducted plate melts into magma Subduction occurs Magma currents converge Asthenosphere

21. The Philippine Plate collides with the Eurasian Plate Volcanic arc Volcanic island Volcano 2. Ocean-Ocean Collision The Eurasian Plate The Philippine Plate Mantle

22. 2 Ocean-ocean collision Watch a video clip of the formation of Surtsey, a volcanic island in southern Iceland Please click to browse online Aleutian Islands Kuril Islands Ryukyu Islands Marianas Islands Distribution of ocean trenches and volcanic island arcs

23. 3 Ocean-continent collision What happens when the South American Plate collides with the Nazca Plate? Nazca Plate South American Plate

24.  3 Ocean-continent collision Fold mountain (____________) The Andes Reverse ________ faults Volcanoes ____________ Pacific Ocean Ocean trench (________________) Peru-Chile Trench Sedimentary rock Earthquake ____________ _____________ force Compressional South American Plate Nazca Plate Denser plate _________ and melts into magma subducts Magma rises through cracks Asthenosphere Magma currents converge

25. 3 Ocean-continent collision What landform can we find at the destructive plate boundary between the North American Plate and the Juan de Fuca Plate? Other example Fold mountain (The Rockies)

26. Aleutian Islands The Aleutian Islands consist of five island groups. This photo shows three of the five island groups from space. Aleutian Trench (Credit: NASA) The Aleutian Islands

27. Mid-oceanic ridges Cracks produced. Magma rises from the asthenosphere When the two plates diverge, magma rises from the asthenosphere through the cracks between them, and pushes the plates up at the edges of the crack. Mid-oceanic ridge (Mid-Atlantic Ridge) Atlantic Ocean Magma cools, solidifies and forms a mid-oceanic ridge. Eurasian Plate North Amercian Plate Eurasian Plate North American Plate The ridge formed from the divergence of the North American Plate and the Eurasian Plateis called the __________________. It is the longest in the world. Magma currents diverge A fissure running along the Mid-Atlantic Ridge in Almannagjá, Iceland Asthenosphere (Credit: Ng Kim Hung) Mid-Atlantic Ridge

28. Mid-oceanic ridges The Mid-Atlantic Ridge is not a smooth continuous line since the constructive plate boundary there is broken. Mid-Atlantic Ridge What is happening there?

29. A B Mid-oceanic ridges The divergence of magma currents drivesthe two sections, I and II, to spread in the same direction. Transform fault Section II Section I Between A and B,the movement of plates at both sides is in opposite directions. This part is called a transform fault.

30. Rift valleys

31. Submarine volcanoes and volcanic islands The divergence of magma currents forms cracks,which extend into the asthenosphere. East Pacific Ridge Cracks develop under tensional force Volcanic island (Easter Island) Submarine volcanoes The pressure of magma is released. Vulcanicity occurs and forms __________ __________. Nazca Plate Pacific Plate submarine volcanoes When these volcanoes rise above the sea level after repeated eruptions,they form _________ _________. Magma currents diverge Asthenosphere Formation of an volcanic island along the East Pacific Ridge volcanic islands