1. Chapter 4 Lesson 1 Plate Tectonics

2. What Are Earth’s Layers

3. Earth’s Layers Core- central part –Inner Core – solid metals –Outer Core – liquid metals Mantle – thick layer of solid and molten rock that surrounds the core Lower – solid rock Upper – 2 parts Lithosphere – solid- upper mantle & crust Asthenosphere – upper mantle – melted rock

4. Crust –Thin layer of solid rock that makes up the outermost layer. –Where we live Atmosphere – –All gases that surround the Earth Hydrosphere –All of Earth’s liquid and solid water (lakes, oceans, rivers, glaciers) –Covers 70% of the Earth

6. Landforms – a physical feature of the Earth’s surface

7. Earth ~200 million years ago

8. The Continental Drift Hypothesis Geologist – person that studies rocks Thought of by Alfred Wegener in 1915. Continents "drifted" to their present positions. Supercontinent Pangaea started to break up about 200 million years ago.

9. Continental Drift: Evidence Geographic fit of South America and Africa Fossils match across oceans Rock types and structures match across oceans Ancient glacial features

10. Tight fit of the continents, especially using continental shelves. Continental Drift: Evidence

11. Continental Drift: Evidence Fossil critters and plants

12. Continental Drift: Evidence Correlation of mountains with nearly identical rocks and structures

13. Continental Drift: Evidence Glacial features of the same age restore to a tight polar distribution.

14. Presumably, Pangaea was ripped apart by such continental rifting & drifting.

15. What causes the continents to move? Plate Tectonics Theory to explain how forces deep within Earth can cause seafloors to spread and continents to move.

17. Tectonic Plates

18. Continental Divergent Boundary Example: Red Sea / E. African Rift

19. Magma – hot melted rock Tension – push or a stretch on the plates Seafloor Spreading – caused by magma pushing on the plates

20. Mid Ocean Ridges - underwater mountain ranges

21. Subduction – when one tectonic plate can sink under another plate- crust gets recycled back into the mantle

23. Mountain Formation Compression – a squeezing or pushing together of the crust This creates folded mountains.

24. Fault – deep cracks in the Earth’s crust where rocks move in the opposite direction Fault Block Mountain –Caused by tension when one block of rock moves down –Sierra Nevada Mountains