Welcome to Geology GEO B10

1. Welcome to GeologyGEO B10 Instructor Jack Pierce Room DST 118 SILENCE YOUR CELL PHONE • Tuesday, August 26, 2010 • Attendance • Geology Introduction 6:00 – 9:10 pm - Tuesday

2. What is Geology? Geo ( ) + logy ( ) Study of the Earth More specifically: materials that compose the earth minerals / rocks processes that shape the earth volcanoes rivers glaciers earthquakes EARTH STUDY or SCIENCE

3. Geology is divided into two broad subject areas: Physical Geology / Historical Geology • Physical Geology: • understanding the processes on earth below and above the • earth surface and the materials (rocks) involved with these • processes erosional processes occurring above the surface earthquakes occurring below the surface transferring energy to the surface processes below the earth’s surface that move rigid plate material on the surface

4. Historical Geology • understanding the evolution of the earth and its life forms • from its origins to the present day • involves investigations into stratigraphy (rock layers), and • paleontology (the fossil record) layers of rock deposited one layer over another– preserving evidence to the origin of the earth “The rock record” fossils- preserved animal/plant remains in the earth’s crust demonstrating the progression of life throughout earth’s history

5. The Geologic Time Scale • attempts to organize 4.6 b.y. • of the earth history • created from both relative • and absolute dating processes • based on fossil succession and • relative dating principles. Age of Reptiles Amphibians Age of fish When does the presence of man appear on the geologic time scale? Invertebrates

6. Humans and Our Earth How long have humans inhabited the earth? Jan Jan Age of dinosaurs 4.6 billion years Man began inhabiting the earth (2 million years ago) --December 31, the last 30 seconds of the year!!!! How has man impacted earth in the last 5000 years (the beginning of reasonably modern times) 34

7. Specifically, geology is defined as: the study of the planet earth--- materials of which it is made, the internal/external processes that act on these materials which produce new materials (rock types) and the history of the planet and its life forms since its origin • Specific disciplines within the field of geology • Seismology • investigate the occurrence of earthquakes • Economic geology • formation/occurrence of mineral resources • Volcanology • investigates volcanoes and volcanic eruptions • Hydrogeology • investigation of surface/subsurface water processes

8. I geology class Discuss with a friend: • What is the specific definition • of geology? • 2. Describe the differences between • physical and historical geology. I will get an A on my exams and quizzes

9. How does the view of Earth influence the way we study earth?? What do you see? • Various “systems” within the earth that interact • with one another -– called Earth System Science • Systems are NOT individually studied • How one system impacts another • system 11

10. Earth as a System: • How systems exchange matter and energy Which system is the Earth? SUN SUN SUN Isolated System Open System Closed System No exchange of matter orenergy Exchange of energy but not matter Exchange of both matter and energy 12

11. The Fragile Earth – A CLOSED system: • Any change in a closed system will affect other • systems. • The amount of matter on earth is “fixed” – “We ain’t got • no more” --- This is all we have. • When we dispose of waste, it’s still here. The waste will • remain within the closed boundaries of earth. X “There is no away to throw things to.” x x 13

12. I this geology class. Discuss with a friend: • Define a system as discussed in • earth science. • 2. Differentiate between an open, closed, • and isolated system. • 3. Explain why earth is considered a closed • system. I will get an A on my exams and quizzes. 14

13. The fragile earth as a closed system is supported by four interrelated open systems. Lithosphere Represents the solid earth: minerals, rocks, and interior Biosphere: Includes all living organisms on land, in water, and in air Atmosphere: Thin blanket of gas keeping life alive, warm, and protected Hydrosphere: Interaction of all water processes, only planet with water, 71% ocean 12,500 feet deep, streams, lakes, groundwater Geosphere Interaction of all open systems 15

14. Cycles and Interactions Explored in Geology There are three (3) main earth cycles and within each cycle, multiple open systems exist. Hydrologic Cycle describes the movement of water through reservoirs of the earth system (rivers, water vapor, groundwater) The Rock Cycle internal/external earth processes that produce new rock, modifies rock, transport rock, and breaks rocks down The Tectonic Cycle movement and interaction between rigid lithosperic plates, internal earth processes producing divergent, convergent, and sliding plate motions

15. I geology class I geology class • Define the four major open systems and • give an example of how systems may • interact with one another. • Define the three major cycles used to • explore geologic processes and give an • example of how these cycles may • interact with one another. I will get an A on my exams and quizzes

16. 8. The earth’s place in the solar system Uranus Neptune Jupiter Saturn Outer planets Jovian planets Gas planets Earth Mars Venus Low densities Mercury Inner planets Terrestrial planets SUN High densities 28 Asteroid Belt

17. Lithosphere Cont/ocean crust Upper mantle 2.8 g/cm3 Crust Asthenosphere ductile rock Mantle -Solid Si,O,Fe,Mg,Ca 5.5 g/cm3 Mantle Why are densities arranged from heavy (core) to lightest (crust)? Core Temp: 5000 C Source of magnetic field Outer Core Molten – Ni, Fe 11.5 g/cm3 Chemical Differentiation Inner Core Solid- Ni, Fe 12.5 g/cm3 29 The earth’s interior

18. What makes earth unique?? • Oxygen, water, life • oxygen atmosphere • no O2 on other planets • the hydrologic cycle • Soil accumulation • weathering of rocks • various soil types • Plate Tectonics • moving continents • formation of landforms • from interacting plates 30

19. Plate Tectonics • The movement and interactions of large • fragments of earth lithosphere (called plates) • earthquakes • new landforms • volcanoes • new climatic regions on the earth • creation of new rock types on the crust • Oceanic Crust • Thin, dense (Fe, Mg) young rock –basalt • underlying the ocean floor • Continental Crust • Thicker, less dense (Si,O) older rock – granite • making the bulk of the earth’s land 31

20. Plate Tectonics!!! Scientists use fossil evidence, sea floor evidence, and climatic evidence to reconstruct the continents!!!!!!– HOT TOPIC 32

21. I Earth Science. Discuss with a friend: • Name the planets in their proper order. • 2. Describe the layering of the earth • using lithosphere, asthenosphere, • mantle, and core; explain properties. • 3. Describe chemical differentiation. • 4. Present at least 3 reasons why the • earth is unique. I will get an A on my exams and quizzes. 33

22. Geophilosophical Questions • Is the Earth old or considered young? • Are earth process rates rapid or slow? • How can rock (considered 2-b.y. old) have the • same composition of present rock produced • today? • If mountains are built through tectonic processes, • why can’t we make obvious observations? • In terms of geologic time, why is it possible for a • storm to erode 2-million years of rock formation • in a single day?

23. Historical aspects about geology There are two schools of thought on the geologic history and processes that formed our earth. Catastrophism vs. Uniformitarianism 4

24. Catastrophism: (mid-1600’s) powerful geologic events that shape the earth in a single incident Volcanic eruptions Earthquakes Massive floods Landsliding 5

25. Catastrophism: (mid-1600’s) • published by Anglican Archbishop, James Ussher • determined that earth was only a few thousand years old – created in 4004 BC • suggested that earth landscapes are fashioned by great catastrophes – features form rapidly • an attempt to fit the formation of earth features into a short amount of time (6000 years – Biblical philosophy- creationist viewpoint) 6

26. Uniformitarianism – Birth of Modern Geology • “The present is the key to the past.” Uniformitarianism states: Physical, chemical, and biological laws that operate today have also operated in the geologic past. • Proposed by James Hutton – late 1700’s • argued using the “rock cycle” concept • argued using earth processes that can • be observed • What is required? TIME 7

27. The Uniformitarianism philosophy Do geologic processes act slowly or rapidly? How many catastrophic events take place/day? When was the last major volcanic eruption? When was the last major earthquake? How long does it take a river to carve a canyon? How fast are the continents moving? Do you consider yourself a catastrophist or a uniformitarianist? 8

28. Taking Uniformitarianism literally – Problem with “U” Rates and intensities of geologic processes change over time. Example: 10,000 years ago, large land masses were covered in ice. Different type of geologic environment than today Different intensity Different rates of erosion Given the concept of Uniformitarianism, would you consider the earth to be very OLD or very YOUNG? 9

29. I geology class. Discuss with a friend: • Describe the differences between • catastrophism and uniformitarianism. • 2. Provide at least 2 examples each of • catastrophism and uniformitarianism. • 3. Identify “problems” with both philosophies. I will get an A on my exams and quizzes. 10

30. Why do we care and study our earth (geology)? • Earth resources: • societies depend on minerals and rocks for material • resources • soils that produce agriculture products • the availability of fresh water for everyone • Geologic hazards: • volcanic eruptions, landslides, earthquakes, floods • (when does nature become a geologic hazard?) • The uniqueness of earth • constant fascination and can give one geologic chills • earth processes may open the door for other planetary • processes Students need the science requirement for their degree!