1. Introduction to Earth Science
Or, How The Earth Works

2. Branches of Earth Science
Geology
Solid Earth Much Larger than Other Parts
Many More Kinds of Materials
Preserves a History
Meteorology – Climatology
Oceanography
Astronomy
Planetary Geology

3. The Earth Systems External Effects (Astronomical)
Atmospheric Circulation
Oceanic Circulation
Hydrologic Cycle
Rock Cycle
Plate Tectonics

4. The Solid Earth

6. Earth and the Universe (external effects)
Earths’ Rotation (Day-Night)
Lunar Effects (Tides)
Annual Variation (Seasons)
Precession and Orbit Variations (Ice Ages?)
Galactic Rotation (250 m.y. period)
Unpredictable Events
Nearby Supernovae
Meteor Impacts
Long-Term Evolution of Sun

7. Atmospheric Circulation
Unequal Solar Heating
Equator to Pole
Day - Night
Different Surfaces
Buoyancy
Heating and Cooling
Coriolis Effect
High and Low Air Pressures
Fronts and Air Masses

8. Oceanic Circulation Surface Currents - Driven by Winds
Thermohaline - Deep Circulation
Evaporation makes water more saline and denser
Freezing makes water more saline and denser
Cold water is denser than warm water

9. Surface Currents

10. Thermohaline Circulation

11. Hydrologic Cycle Evaporation from Oceans Precipitation on Land
Infiltration into Ground (Ground Water)
Runoff (Erosion)

12. Hydrologic Cycle

13. Water Principal Agent in Modifying Earth’s Surface
Medium for Storing and Distributing Global Heat
The Universal Solvent
Essential for Life
Destructive to Rocks
Lowers Melting Point of Rocks
Reduces Strength of Rocks Under Pressure

14. The Rock Cycle New Rocks Exposed by Erosion
Rocks Broken Down Mechanically and Chemically (Weathering)
Components Transported by Erosion
Components Cemented into Sedimentary Rocks
Burial and Heating creates Metamorphic Rocks
Melting Creates Igneous Rocks

15. The Rock Cycle

16. Plate Tectonics Outer Crust of Earth Moves a Few cm/yr
Driven by Convection in Earth’s Interior
Accounts For:
Earthquakes
Volcanoes
Mountain-Building (Orogeny)
Configuration of Continents

17. Plate Tectonics

18. Plate Tectonics and Resources

19. Configuration of Continents
Oceanic Circulation
Weather and Climate Patterns
Deserts
Mountains and Rain Shadows
Pathways for Migration
Ecological Niches

20. Some Unique Aspects of Geology
Importance of Relationships
Sequential
Spatial
Importance of Time
Distinctive Problems of Evidence
Slow Rates
Rare Events
Destruction of Evidence
Inaccessibility

21. Some Geologic Rates Cutting of Grand Canyon 2 km/3 m.y. = 1 cm/15 yr
Uplift of Alps
5 km/10 m.y. = 1 cm/20 yr.
Opening of Atlantic
5000 km/180 m.y. = 2.8 cm/yr.
Uplift of White Mtns. (N.H.) Granites
8 km/150 m.y. = 1 cm/190 yr.

22. Some Geologic Rates Movement of San Andreas Fault
5 cm/yr = 7 m/140 yr.
Growth of Mt. St. Helens
3 km/30,000 yr = 10 cm/yr.
Deposition of Niagara Dolomite
100 m/ 1 m.y.? = 1 cm/100 yr.

23. 1 Second = 1 Year 35 minutes to birth of Christ 1 hour+ to pyramids
3 hours to retreat of glaciers from Wisconsin
12 days = 1 million years
2 years to extinction of dinosaurs
14 years to age of Niagara Escarpment
31 years = 1 billion years

24. Some Unique Aspects of Geology (Continued)
Reliance on Inference and Deduction
Intrinsically "Unsolvable" Problems
Ancient Landscapes
Mass Extinctions
Ancient Ocean Basins

25. Scientific Principles in Geology
Parsimony (Keep It Simple)
Superposition
Uniformitarianism
Using these, plus observation, we establish facts about Earth Processes

26. Parsimony The simplest explanation that fits all the data is preferred
Doesn’t guarantee that things must be simple!
Theories with lots of ad hoc or unsupported ideas are probably wrong.

27. Superposition: Road Cut, Superior, AZ

28. Geologic Map

29. Uniformitarianism Continuity of Cause and Effect
Apply Cause and Effect to Future - Prediction
Apply Cause and Effect to Present - Technology
Apply Cause and Effect to Past - Uniformitarianism