1. GY 112 HISTORICAL GEOLOGY

2. What does Historical Geology deal with?
Earth’s origin and evolution
Changes in the distribution of lands and seas,
Growth and reduction of mountains, and
Succession of animals and plants through time

3. Why is Historical Geology important?
The present is the key to the past:
It allows us to learn from past mistakes and make plans for the future
It provides insight into catastrophic events occurring in the past that resulted in mass extinctions and climatic changes, and
It helps to explain the formation and location of natural resources such as fossil fuels, minerals, and energy resources

4. Three Great Themes in Earth History
Deep Time
Evolution of Earth’s Nonliving Features
Evolution of Earth’s Life

5. REVIEW OF GY 111 CONCEPTS

6. EARTH FORMATION
Theories
Big Bang
Nebula Theory

7. EARTH FORMATION Time Universe Age: 13.82 Billion Years
Earth Age: Billion Years

8. EARTH FORMATION Universe Organization Universe Galaxies Stars
Solar Systems
Planets
Moons
Asteroids
Meteoroids

9. EARTH FORMATION Earth’s Stages of Development
Stage 1 – Initial Formation (Molten State, Moon Formation)
Hadean Eon (4.52 – 4.2 bya)
Stage 2 – Lithosphere (Land), Hydrosphere (Water), Atmosphere (Air)
Archean Eon (4.2 – 2.5 bya)
Stage 3 – Ancient Life (Oxygen Poor Environment) - Microbes
Proterozoic (2.5 – bya)
Stage 4 – Modern Life (Oxygen Introduced) – Our present time
Phanerozoic (0.542 bya – Present)

10. EARTH’S CHARACTERISTICS
Subsurface Features
Compositional Layers
Crust (silicon/oxygen)
Mantle (magnesium)
Core (nickle/iron)
Structural Layers
Lithosphere (Solid)
Asthenosphere (Putty)
Mesosphere (Solid)
Outer Core (Liquid)
Inner Core (Solid)

11. EARTH’S CHARACTERISTICS
Surface Features – “Geomorphology”
Mountains
Landforms
Deserts
Karst Topography
Valleys
Beaches
Etc.

12. EARTH’S COMPOSITION Chemistry Silicon & Oxygen (2 major elements)
Minerals
Rocks
Classified based on composition and texture
Soil
Note: Minerals and rocks can be considered nonliving fossils, providing clues as to the location and processes involved in their formation.

13. EARTH’S PROCESSES Constructive Processes Destructive Processes
Mountain Building (Referred to as “Orogenic Events”)
Volcanism
Earthquakes
Destructive Processes
Weathering & Erosion

14. EARTH’S MECHANISMS Plate Tectonics
Responsible for Earthquakes, Volcanism, and Orogenic Events.
Involves the creation and recycling of Earth’s Crustal Material

15. THE END