Our Amazing Planet

1. Our Amazing Planet

2. Planet Earth • Earth’s Layers

3. Crust • Earth’s thin outermost layer. • Continental Crust (land) - thick low density rock (granite). • Oceanic Crust (sea floor)- thin dense rock (basalt)‏

4. Mantle • Earth’s thickest layer made of dense iron-rich super heated soft rock. • Where convection currents occur.

5. Core • Earth’s innermost layer made of hot, dense iron and nickel. • Outer core - Liquid • Inner core - Solid

6. Lithosphere • Earth’s outermost layer • Includes the crust and solid upper part of the mantle. • Divided into huge pieces called “Tectonic Plates”. • Move around on top of the asthenosphere - very hot, soft layer of the mantel.

7. Earth’s Tectonic Plates

8. Continental Drift • Theory that the Earth’s continents move over time • Proposed by Alfred Wegener in the early 1900’s • Evidence of Continental Drift: • Continents fit together • Similar fossils records • Similar rocks and minerals • Similar rock formations and striations • Similar climatic conditions – Glaciations

9. Evidence of Pangaea

10. Continents Fit Together

11. South America and Africa

13. Similar Fossil Records

15. Similar Mountain Ranges

16. Similar RocksRock Striations Match

17. Other Evidence - Glaciations

18. Sea Floor Spreading • Occurs where tectonic plates spread apart at Mid Ocean Ridges • Magma rises from inside the Earth creating new sea floor. • New sea floor pushes the existing sea floor out explaining why continents move. • Evidence that supports the theory of Continental Drift.

19. Sea Floor SpreadingNew crust is formed at mid-ocean ridges spreading the sea floor

21. Mid-Atlantic Ridge

23. Causes Sea Floor Spreading The main cause of plate tectonics Convection Currents Hot magma rises and cooler magma sinks in the Earth’s Mantel Convection Currents in the Mantle

24. Tectonic Plate Boundaries

25. Convergent Boundaries • Tectonic plates collide - • Forms trenches, mountains, and subduction zones • CTMS – Convergent – trenches – mountains - subduction

26. Convergent BoundariesSubduction Zones Creates trenches in the ocean and mountains and volcanoes on land

27. Divergent Boundaries • Tectonic plates move apart • Forms Mid Ocean Ridges in oceans and Rift Valleys on land • East African Rift • Mid-Atlantic Ridge

28. Mid-Ocean Ridges • Chain of volcanoes at the middle of the ocean floor. • Causes Sea Floor Spreading • Magma comes up from inside the Earth, cools and hardens and creates new sea floor. • The rock at the mid-ocean ridge is the youngest and gets older as it moves farther away from the ridges.

29. Mid-Atlantic Ridge

30. Transform Boundaries • Tectonic plates slide past each • Forms Fault lines • San Andreas Fault in California

33. Volcanoes and EarthquakesMost Occur at Tectonic Plate Boundaries

34. Ring Of Fire

35. Ring of Fire • Volcanoes around the Pacific Ocean caused by tectonic plates colliding into each other creating subduction zones at CONVERGENT boundaries.

36. Hot Spots • Areas in the middle of tectonic plates where magma inside the Earth rises through the crust and forms volcanoes. • Like the Hawaiian Islands

37. Hawaii Islands

38. Super Volcano • Yellowstone National park • Underground volcano caused by another Hot Spot • 3 overlapping calderas underground is believed to have formed from a hot spot creating Yellowstone’s “Super Volcano”

39. Yellowstone