Earth Systems

1. Earth Systems

2. The Relatively Recent Earth • A “blue marble”. • Divided into spheres classified according to the make-up and characteristics of the materials. • One big system with a finite set of resources.

3. The Environment What components make up the environment?

4. 5 systems working together • Lithosphere – rock • Atmosphere – gases • Hydrosphere – water liquid • Cryosphere – water solid • Biosphere – living organisms

5. 1. Lithosphere • The ever-changing solid portion of the Earth. • The “plates” • What we live on • The source of most of our nonrenewable resources”.

6. 2. Atmosphere • A delicate balance of gases that envelopes the Earth • N2 from primitive atmosphere • H2O from volcanic activity • O2 from oceanic phytoplankton

7. 3. Hydrosphere • The water that covers 71% of the surface of the Earth. • Oceans • Lakes • Rivers/Streams • Groundwater • ***4. frozen water (cryosphere)****

8. 5. Biosphere • The organic realm of life. • Intertwined within the other surface spheres.

9. Formation of Earth • 4.6 Billion years ago • A molten, undifferentiated Earth. • Bombarded by meteorites • Materials begin to cool • Heavy materials sink to center, Lighter ones stay at surface – resulted in uneven distribution of minerals

10. Layers of Earth • constantly changing as a result of processes taking place on and below its surface. • Core: innermost zone with solid and molten, extremely hot. • Mantle: solid rock with a outer part is melted rock = magma • Crust: Outermost zone underlies continents; brittle

12. Spreading center Collision between two continents Ocean trench Oceanic tectonic plate Oceanic tectonic plate Plate movement Plate movement Tectonic plate Oceanic crust Oceanic crust Subduction zone Continental crust Continental crust Material cools as it reaches the outer mantle Cold dense material falls back through mantle Hot material rising through the mantle Mantle convection cell Mantle Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Hot outer core Inner core

13. Thinking questions??? • What are the physical results of tectonic plates moving? • On the surface of Earth, this movement affects the biosphere – how? • Be specific – give examples

14. Changes are recorded as Geologic Time Scale

15. Geologic Time Scale Activity • Represent the length of your time period using a piece of paper towel • 1 million years = 1 inch • On this piece of towel write: • name of Time period • write/draw 1 significant Geological event AND 1 significant Biological event

16. Geologic Time Scale Activity Day 2 Decide how you will present your time period to the class Did you draw land mass change? Fact check your time period using:

17. GEOLOGIC PROCESSES • Huge volumes of heated and molten rock moving around the earth’s interior (in convection cells) form massive solid plates that move extremely slowly across the earth’s surface. • Tectonic plates: huge rigid plates that are moved by floating on magma or molten rock. • Hot spots where plumes of magma rises to lithosphere

18. The Earth’s Major Tectonic Plates Figure 15-4

19. Results of plate movement • On surface this movement affects the biosphere - changing climates, removing/forming geographic barriers, species evolve or become extinct • Recorded as Geologic Time Scale

20. Early earth video 5min https://www.youtube.com/watch?v=QDqskltCixA • 3 Eras • Extinctions • Coal Formations

21. 5 Mass extinctions • Ordovician • Devonian • Permian – Greatest 90% marine species, 70% land vertebrates • Triassic • Cretaceous – 50% all species (+dinos) • #6 currently happening – human caused (anthropogenic)

22. Determining the age of fossils and rock layers • Relative dating – determines order of events occurring by comparing rock layers, not age

23. Determining the age of fossils and rock layers • Absolute/radiometric dating – original parent isotope breaks down into daughter isotope at constant rate

24. Uses of radioactive isotopes Irradiation of food Cesium-137 tests age of wine Test for leaks in underground water pipes

25. Half-life • Half-life is the time taken for the radioactivity of an isotope to fall to half its original value. • Ex: Iodine-131 has a half-life of 8.1 days

27. Practice problems radiometric dating • calculators on APES exam • Write out work = less likely to make mistakes • Half life – radioactive parent material vs. daughter material • 10 half-lives for radioactive material to be “safe” to handle

28. Start with easier practice problems 1. How many half lives occurred if the mass before is 32g and the mass afterwards is 1g?

29. Start with easier practice problems 2. How much mass is left after 3 half lives if mass before decay is 1024kg?

30. Start with easier practice problems 3. What was the mass before nuclear decay if 4 half lives occurred and the mass afterwards was 8g?

31. Start with easier practice problems • Answer questions on class worksheet • Add to WS one more practice problem - How many grams of C-14 will remain after 17,200 years of an original sample of 300 grams?

32. Warm up question – half-life • The half-life of chromium-51 is 28 days. What fraction of chromium would remain after 168 days?

33. Earth’s Major Tectonic Plates 1-2 inches per year

35. 3 types of tectonic plate boundaries • The extremely slow movements of these plates cause them to move apart form each other, grind into one another, or slide past each other.

36. 3 types of Tectonic Plate Boundaries Trench Volcanic island arc Craton Transform fault Lithosphere Rising magma Lithosphere Subduction zone Lithosphere Asthenosphere Asthenosphere Asthenosphere Divergent plate boundaries Convergent plate boundaries Transform faults

37. 1. Divergent Plate Boundary • the plates move apart in opposite directions • Most common under ocean aka Seafloor spreading • Example: Mid-Atlantic Ridge in middle of Atlantic Ocean • Animation - http://geology.com/nsta/divergent-boundary-oceanic.gif

38. 2. Convergent plate boundary • Plates push together by internal forces, usually pushing one below the other. • Geologic features… • Mountains • Subduction zone • Volcano • Earthquake • Island arc • Animation - http://geology.com/nsta/convergent-boundary-oceanic-continental.gif

40. Volcanic hot spot

41. 3. Transform Fault boundary • Plates slide next or past each other in opposite directions along a fracture. • Example: Pacific plate off the coast of California • Lots of volcanoes and earthquakes occur here • The largest plate and the location of the ring of fire. • California will NOT fall into the ocean!

43. A B C

44. Importance of plate movement • adds new land at boundaries, • produces mountains, trenches, earthquakes and volcanoes • Thus creates new ecosystems

45. Richter scale • Measure magnitude of earthquake (rocks rupture suddenly along fault) • Epicenter – on Earth surface above location of rock rupture

47. Underwater Earthquakes can trigger tsunami • Water quickly displaced • Saltwater inland • Destroy habitat • Kills organisms • 3min video https://www.youtube.com/watch?v=Wx9vPv-T51I

50. Mapping activity • Draw in continents • Shade in earthquake zones • Draw red triangles for volcanoes • Resource: Google images or Textbook pages 211 and 215 • Compare to Google map of earth using satellite layer on your phone