What is the Earth System?

1. What is the Earth System? • The atmosphere (Air) extends up from the Earth surface for several hundred kilometers. • The biosphere (Life) is all living things, from single-celled bacteria to plants and animals. • The geosphere (Land) includes all minerals, rocks, molten rock, sediments, and soils • The hydrosphere (Water) includes the ocean, rivers, lakes, streams, groundwater, water vapor. • (The cryosphere (Ice) is the frozen part of the Earth system and includes snow, glaciers, and sea ice.)

2. All systems are connected “When we try to pick out anything by itself, we find it hitched to everything else in the universe.” John Muir“My First Summer in the Sierra” 1911

3. Energy Starting Point • It all starts at the Sun • Energy from the Sun is the ultimate source of almost all energy in the Earth system!

4. Geology – study of the earth

5. I. Earth’s Structure • Layers of the Earth– 1. crust – (.5%) – top layer; thinnest under oceans (Lithosphere) 2. Mantle (67%) - a. Lithosphere - (rigid portion - plates) b. Asthenosphere – flows due to added pressure 3. Outer Core – liquid; (iron & nickel) 4. Inner Core – solid; (iron & nickel)

6. Layers of the Earth – temp & pressure increase as you move down to center

7. B. Rocks & Minerals – solid portion of the crust 1. Mineral – solid, inorganic material with the same chemical make-up, crystalline structure, & specific properties like color, hardness; ex. salt, mica, pyrite, quartz, diamond 2. Rock – solid, inorganic material made up of 2 or more minerals

8. 3. Types of Rocks a. Igneous – crystalline solids which form directly from the cooling of magma/lava; ex. basalt, pumice, granite b. Sedimentary - the accumulation/layering & compacting of small broken off pieces of pre-existing rocks; sandstone, limestone, shale c. Metamorphic – rocks subjected to different temperatures & pressures to “change form”; ex. marble, slate, quartzite

9. Types of Rocks Igneous Sedimentary Metamorphic Marble Slate Pumice Sandstone

10. 4. Rock Cycle

11. II. Plate Tectonics • Theories 1. Continental Drift – 1929 – Alfred Wegener – proposed continents were originally 1 & then moved apart

12. 2. Seafloor Spreading – 1960s – Harry Hess -seafloor itself moves (and carries the continents with it; process that occurs where 2 plates meet - new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. )

13. B. Earth’s Plates - composed of 7 (8) large or 30 total sections of the lithosphere (upper mantle + crust) that move around on the plastic-like asthenosphere: 2 – 10 cm/yr at different directions & speed

14. C. Plate Movement • The heat from the core of the earth reaches the mantle. Heat is transferred to the fluid layer and the resulting convection currents cause the plates to move. • Plate Boundary – place where 2 plates meet & move

15. D. Types of Plate Movement 1. Convergent Boundary - Place where plates crash or crunch together; can form mts., volcanoes, earthquakes

16. 2. Divergent Boundary - Place where plates are coming apart; rifts or valleys form here (Great Rift Valley in Kenya or the rift near the Rio Grande; can form volcanoes or earthquakes

17. 3. Transform Boundaries– Place where plates slide past each other; cause lots of earthquakes

18. E. Results of Plate Movement -Volcanoes & Earthquakes Tectonic Plates, Volcanoes & Earthquakes

19. III. Forces on Earth to cause Landforms (combination) • Destructive Forces – processes that destroy landforms; 1. 2 types: weathering (slow) and Erosion (fast) 2. Ex. landslides, volcanic eruptions, earthquakes (faulting), floods B. Constructive forces:forces that build up an existing landform or create a new one. 1. caused by: water, gravity, wind and glaciers. 2. Ex: deposition of sediment, landslides, volcanic eruptions, floods

20. C. Types of Forces at Work1. Weathering – breaks rocks into sediments a. Mechanical weathering: the breaking of rock into smaller pieces by forces due to gravity, ice, plant roots, or other physical forces. b. Chemical Weathering: the changing of materials in a rock by chemical processes.

21. 2. Erosion – destructive movement of materials away from one place by wind, water, ice, & gravity Water erosion wind erosion glacial erosion

22. 3. Deposition: the placing of materials in a new place (constructive force). Ex. Sandbars River Deltas – at mouth of Mississippi River Deposition by volcanoes

23. F. Examples of Forces at Work • Landslides – gravity quickly pulls rock & dirt downhill 2. Floods – great flow of water over (usually dry) land

24. 3. Earthquakes - A sudden movement of the earth's crust caused by the release of stress accumulated along geologic faults or by volcanic activity 4. Volcanic Activity - rupturein the crust, which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface

25. III. Applied Geology • Economic geology – locate & manage earth’s natural resources – ex. petroleum, coal, minerals B. Mining geology – extraction of minerals from the Earth (petroleum geology – petroleum & natural gas) C. Engineering geology –works to design structures based on the features of the Earth

26. 4. Environmental geology – looking at environmental issues related to natural habitat & water issues 5. Natural hazards geology – study of the natural hazards of earth to enact safe building codes & warning systems used to prevent loss of property & life