1. Geology
Ch. 8

2. Geologic Time Scale Eon  Eras  Periods  Epochs  Stages
Largest  Smallest
Era
Cenozoic – Current, Ice Age, First Man
Mesozoic – Building of Rocky Mtns, Dinosaurs, Birds
Paleozoic – Reptiles, Amphibians, Fish, Building of App. Mtns
Precambrian – Oldest, Marine Life

3. Principle of Superposition
The deeper you dig the old the material found.

4. Earth Structure
Crust - .5% of Earths total mass, oceanic and continental crust, Moho – boundary between Earth’s crust and mantle Mantle – Most of Earths mass, Aesthenosphere = plastic like Core – Mostly Iron

5. Figure 10-2 Page 204 35 km (21 mi.) avg., 1,200˚C Crust
Low-velocity zone
100 km (60 mi.)
200 km (120 mi.)
Crust
Mantle
Lithosphere
Solid
10 to 65km
2,900km
(1,800 mi.)
3,700˚C
100 km
Asthenosphere
(depth unknown)
Outer core
(liquid)
200 km
Core
5,200 km (3,100 mi.), 4,300˚C
Inner
core
(solid)

6. Plate Tectonics
Describes the formation and movement of ocean and continental plates
Convection – is the process of heat transfer that causes hot, less dense matter to rise and cool matter to sink
James Hutton – sedimentation, heat, pressure, and other gradual processes over millions of years = causes of most geological changes

7. Plate Tectonics 1. Continental Drift – Alfred Wegner 1915
Pangae – one big continent
fossil evidence, continents fit like a puzzle, similar rocks between North & South America coasts and Africa & Europe
About 15 plates can be found on Earth

8. Plate Tectonics
2. Sea Floor Spreading a. Divergent Boundary – ridges form – Mid ocean ridge b. Transform Boundary – San Andreas Fault c. Convergent Boundary – form trenches in oceans (Pacific Ring of Fire)

9. Pacific Ring of Fire

10. Features of the Crust
Fig p. 205

12. Earthquakes Along a fault along plate boundaries
Focus (Hypocenter) – Where slip occurs
- Epicenter – Above
Seismic Waves – caused by vibrations in the Earth from cracks or shifts in the underlying rock
Seismograph – instrument that records waves
Tsunamis – caused by earthquakes under ocean floor

13. Earthquakes
Waves
P-Waves = Fastest Waves, move through rock, liquid and gases
S-Waves = Slower, only move through rocks
Richter Scale – increments each equal a ten fold increase from the previous increment
Largest U.S. occurred at Prince William Sound (9.2)
Alaska  California  Hawaii
(Greatest risk of earthquakes)

14. Figure 10-9 Page 210 Two adjoining plates move laterally along
the fault line
Liquefaction of
recent sediments
causes buildings
of sink
Earth movements
cause flooding in
low-lying areas
Landslides may
occur on
hilly ground
Shock
waves
Epicenter
Focus
Figure 10-9 Page 210

15. Volcanoes
Fissure – Mid Ocean Ridge, Cracks Shield – Gentle Slope, Mid Ocean Ridge Ex. Mauna Lea, Kilauea Dome – Steep, Convex Slope Ash Cinder – Throws out a lot of ash Ex. Paricutin Composite – Alternate layers of lava and ash, very tall, Ex. Mt. Rainier, Fuji, Pinatubo, Vesuvius Caldera – Crater, Ex. Yellowstone

16. Volcanoes
During Volcanic Explosions most people die from poisonous gases
Tephra – All the different types of matter ejected from a volcano compared to slow moving lava
Volcanic Gases – Water vapor and CO2 = 90 to 95% - Sulfur dioxide, Hydrogen, Nitrogen = <1%
Where do most Volcanoes occur? Boundaries of plates

17. Rock Cycle Figure 10-8 Page 240 Sedimentary Rock Shale, sandstone,
limestone
Transportation
Deposition
Erosion
Heat,
pressure,
stress
Weathering
EXTERNAL PROCESSES
INTERNAL PROCESSES
Igneous Rock
Granite, pumice,
basalt
Metamorphic Rock
Slate, marble,
quartzite
Heat, pressure
Cooling
Magma
(molten rock)
Melting
Figure 10-8 Page 240

18. Rock Cycle Characteristics
Diagenesis – Sediments changed to sedimentary rock
1. Compaction, cementation, recrystallization, and chemical changes

19. Soil Characteristics Holds nutrients & water
Water is filtered & cleaned
Affects chemistry of water
4. 3 Ingredients – mineral, organic matter, open space

20. Soil Formation Parent Material – rock minerals which soil derives
Climate
Living organisms – help decompose
Topography – drainage, elevation, wind erosion, slope

21. Soil Profile
O-Horizon: top, litter (leaves and debris), start of topsoil
A-Horizon: topsoil layer, some inorganic materials and humus which is partially decomposed organic material, Zone of Leaching
E –Horizon – zone of leaching, water
percolates
B – Horizon: subsoil, broken down inorganic
rock, Zone of Accumulation
C – Horizon: parent rock, little or no organic
matter

22. http://www. youtube. com/watch

23. Soils: Formation Fig. 10-12 p. 212 Regolith Bedrock Soil horizons
Soil profile
Humus
O horizon
Leaf litter
A horizon
Topsoil
B horizon
Subsoil
C horizon
Parent
material
Mature soil
Young soil
Regolith
Bedrock
Immature soil
Fig p. 212

24. Soil Characteristics Refer to Fig. 10-15 p. 215
Texture Nutrient Infiltration Water-Holding Aeration
Capacity Capacity
Clay Good Poor Good Poor
Silt Medium Medium Medium Medium
Sand Poor Good Poor Good
Loam Medium Medium Medium Medium
Refer to Fig p. 215

25. Soil Characteristics
Pedocal soils – large accumulations of calcium carbonate

26. Loam
40% sand, 40% silt, 20% clay
Theoretically the ideal soil (AG)

27. Figure Page 217
Water
Water
High permeability
Low permeability

28. Global Soil Erosion

29. Soil Erosion
Sheet Erosion – moves off as a horizontal layer Rill Erosion – fast flowing, small channels in soil Gully Erosion – extreme rill erosion, increase in size of channels Affects of erosion: interferes with wetland ecosystems, reproductive cycles (salmon), oxygen capacity, pH of water

30. Soil Erosion
Desertification – loss of native vegetation, increased erosion, salinization, reduced surface water supply Solution – reduce overgrazing, reduce deforestation, reduce destructive forms of planting, irrigation, and mining; plant trees & grasses to hold soil

31. Soil Erosion
Salinization – water evaporates and leaves behind dissolved salts in topsoil, stunts crop growth, lower yield Solution – do not use land for a couple years, underground drainage pipes, plant salt loving plants (barley, cotton, sugar beet), flush soil

32. Soil Erosion
Waterlogging – saturation of soil with water, rise in water table, saline water envelops deep roots killing plants (near saltwater regions) Solution – utilize BMPs (Best management practices) Conservation tillage, plant waterlogging resistent plants, take land out of production, install pumping stations

33. Terracing Contour

34. Alley Crops Windbreaks

35. Factoids
Dust Bowl: 1930s in Oklahoma, Texas, & Kansas; plowing prairies, loss of grasses that rooted the soil, drought and winds blew most of the topsoil away 1935 Soil Erosion Act: Established the Soil Conservation Service, deals with soil erosion problems, soil surveys, research on soil, provides databases for scientific research