1. The Study of Earth’s History
Chapter 8 Sec 1

2. What you will learn
Earth processes today are similar to those that occurred in the past and slow geologic processes have large cumulative effects over long periods of time.
The history of life on Earth has been disrupted by major catastrophic events, such as major volcanic eruptions or the impacts of asteroids.

3. Geology Geo- means Earth -ology means study of
Geology – the study of Earth
Geologist – scientist who studies the Earth

4. What scientist and philosophers used to think…
Up until the end of the 1700’s people believed that the Earth was only 2000 years old.
They believed that the landforms (mountains, rivers, oceans, valleys, etc) formed suddenly.

5. BOOM!!!
Catastrophism:
This is the idea that geologic change only happens suddenly.
Example: asteroid hitting the Earth

6. Catastrophism
Is this possible? Why or why not?

7. Look on page 234 of your book.
Read figure 1.
Who was James Hutton?
What did he say about geologic processes?

8. Uniformitarianism
Idea that geologic processes occurring now are the same as those in the past. James Hutton came up with this idea.
It is a gradual, slow process.
Example: the gradual erosion that formed the Grand Canyon.

9. Modern Geology
Today scientists believe that NEITHER uniformitarianism nor catastrophism can explain ALL geologic changes.
What do you think is the best explanation for how our Earth came to its current form?

10. Modern Geology cont.
Today it is believed that most geologic change is slow and uniform, but catastrophes or sudden changes have also formed our Earth.
So…. Modern Geology combines both principles of uniformitarianism and catastrophism.

11. Paleontology Does this word sound familiar?
It is the study of the life forms that lived on Earth and how they lived.
A paleontologist studies all fossils (not only dinosaurs) to see how the environment has changed.

12. Rock Cycle Forming of new rocks from other types of rocks
Igneous rocks form from
the cooling of magma.
Sedimentary rock forms from fragments of other types of rocks. THIS IS WHERE FOSSILS ARE FOUND!
Metamorphic rock forms when sedimentary or igneous rock are heated and squeezed (extreme heat and pressure)

13. What you have learned
Catastrophism is the idea that the Earth changed suddenly.
Uniformitarianism is the idea that the Earth changes slowly or gradually.
The rock cycle describes how one form of rock turns into a different form of rock.

14. What to do now…. Write a 6 sentence summary about what you learned.
Introduction sentence (what is the big picture?)
Detail
Why is what you learned important for you science education?