Earth’s Many Cycles

1. Earth’s Many Cycles 10 November 2015 Chapter 18 Presented by Dr. Geller Great Idea: All matter above and beneath Earth’s surface moves in cycles.

2. Chapter Outline • Cycles Small and Large • The Hydrologic Cycle • The Atmospheric Cycle • The Rock Cycle

3. Cycles Small and Large

4. Recycling • Where did the aluminum can go? • Atoms last virtually forever • Different forms • Lava flow bonded to oxygen • Solid rock • Soil • Aluminum metal • Recycling saves energy

5. The Nature of Earth’s Cycle • Earth materials move in cycles • A change in one cycle affects the others • Atoms constantly moving and recycling • Reservoirs • Hydrologic cycle • Atmospheric cycle • Rock cycle • Heat • Hotcold • Sources • Sun • Geothermal processes

6. The Hydrologic Cycle

7. Reservoirs of Water • Amount of water on earth is fixed • Major repositories • Ice caps • Glaciers • Unseen reservoirs • Groundwater • aquifers

8. Movements of Water Between Reservoirs • Hydrologic cycle • Short-term transfer of water between ocean and land

9. The path of groundwater

10. Ocean Currents • Redistribute heat across planet

11. Chemical Cycles in the Oceans • Chemicals in constant motion • Saltiness • Constant over several hundred million years • Primarily determined by Na+ and Cl- ions • Residence time • Chemical cycle

12. Ice Ages • Ice Age • Water locked in glaciers • Glaciers advance from poles • Current ice age • Interglacial period • Earth’s total water is fixed • Ice caps, glaciers grow • Sea level drops

13. Milankovitch Cycles • Milankovitch • Serbian civil engineer • Relationship between earth and sun are affected by variations in earth’s rotation and orbit • Precession • Change in angle of axis of rotation

14. The Atmospheric Cycle

15. Atmosphere • Composition • Nitrogen (78%), Oxygen (21%), Argon, Water Vapor, CO2, Methane, other • Atmospheric Pressure • pressure exerted by atmosphere • Warming • Sun - solar constant is not really constant • greenhouse effect • warming due to the transparency of a substance to radiation at visible wavelengths and opacity to infrared radiation

16. The Greenhouse Effect • Solar energy is the energy source for the atmosphere • In the greenhouse effect, some of this energy is trapped by infrared absorbing gases in the atmosphere, raising the Earth’s surface temperature above what it would be if there was no greenhouse effect

20. Industrial chemicals released into the atmosphere have damaged the ozone layer in the stratosphere

21. The Earth’s atmosphere has changed substantially over time • The Earth’s atmosphere differs from those of the other terrestrial planets in its chemical composition, circulation pattern, and temperature profile • The Earth’s atmosphere changed from being mostly water vapor to being rich in carbon dioxide • A strong greenhouse effect kept the Earth warm enough for water to remain liquid and to permit the evolution of life

22. Structure of the Atmosphere

23. Air Masses: Reservoirs of the Atmosphere • Air mass • Uniform temperature and moisture • Weather • State of the atmosphere • Climate • Long-term average of weather

24. Weather • Five variables define state of atmosphere • Temperature • Ground level • Air pressure • Decreases with altitude • Jet stream • Humidity • Atmospheric water content • Cloudiness • Concentration of water droplets • Prevailing winds • Consequence of atmospheric convection

25. The General Circulation of the Atmosphere • Circulation powered by Sun • Air heated and rises • Cools and sinks • Prevailing winds • Caused by earth’s rotation

26. Common Storms and Weather Patterns • Severe weather • Tropical storms • Hurricanes • typhoons • Tornadoes • Weather cycle • El Nino

27. Climate • Little change over short periods • Influences on climate • Large bodies of water • Ocean currents • Mountain ranges • Earth’s climate • Movement of tectonic plates

28. Understanding Climate • Long-term climate • Oceans • Mountains • Sunlight • Amount radiated back to space • Prediction • Global circulation models

29. The Rock Cycle

30. Rock Cycle Overview

31. Igneous Rocks • Igneous Rocks • Solidify from hot liquid • Types • Extrusive • Solidify at surface • Intrusive • Solidify below surface

32. Sedimentary Rocks • Sedimentary rock • From grains of weathered rock • Formation • Compaction • Cementation • Examples • Sandstone • Shale • Limestone

33. Metamorphic Rocks • Metamorphic rock • Pressure and heat • Not enough heat to melt • Examples • Slate • Schists • Gneisses • Quartzite

34. The Story of Marble • Marble • Metamorphic rock • Process of formation • Begin as limestone • Subjected to heat and pressure • Erosion exposes rocks

35. Surface Building Processes • Faulting • formation of a crack caused by relative movement of rock on either side of a fracture • different types - normal, reverse, thrust

36. Mountains • “elevated parts of the Earth’s crust that rise abruptly above the surrounding surface” • Causes • folding, faulting, volcanic activity

37. Folds • bends in layered bedrock • Anticline /\ • Syncline \/

38. Volcanoes • “hill or mountain formed by the extrusion of lava or rock fragments from magma below” • Different types • shield, cinder cone, composite (composite shown)

39. Earthquakes • Defined as “quaking, shaking, vibrating, or upheaval of the ground” • Earthquake causes • elastic rebound theory • Intensity measure • Richter Magnitude • not linear scale