1. Chapter 4 A trip Through Geologic Time

2. 4.1 Fossils Key Concepts How do fossils form?
What are the different kinds of fossils?
What does the fossil record tell about organisims and environments of the past?

3. 4.1 Fossils Key Terms Fossil Trace fossil Sedimentary rock
Mould
Cast
Petrified fossil
Carbon film
Trace fossil
Paleontologist
Scientific theory
Evolution
Extinct

4. 4.1 Fossils How Fossils Form
Most fossils form when living things die and are buried by sediments.
The sediments slowly harden into rock and preserve the shapes of the organisms.
Fossils found in rock include molds an casts, petrified fossils, carbon films, and trace fossils

5. 4.1 Fossils How Fossils Form
Molds and casts

6. 4.1 Fossils How Fossils Form
Petrified fossils

7. 4.1 Fossils How Fossils Form
Carbon films

8. 4.1 Fossils How Fossils Form
Trace fossils

9. 4.1 Fossils How Fossils Form
Preserved remains

10. 4.2 The Relative Age of Rocks Key Concepts
What is the law of superpostions?
How do geologists determine the relative age of rocks?
How are index fossils useful to geologists?

11. 4.2 The Relative Age of Rocks Key Terms
Absolute age
Law of superposition
Extrusion
Intrusion
Fault
Unconformity
Index fossil

12. 4.2 The Relative Age of Rocks The Position of Rock Layers
Law of Superposition –
In horizontal sedimentary rock layers the oldest layer is at the bottom.
The layers get younger and
they get closer to the top.

13. 4.2 The Relative Age of Rocks Determining Relative Age
Clues from igneous rock –
Extrusion - Layers where lava hardens on the surface.
Intrusion – When the magma hardened inside the planet. It is always younger that the layers around it.

14. 4.2 The Relative Age of Rocks Using Fossils to Date Rocks
Index fossil is one that only appears in a specific layer of sediment.

15. 4.3 Radioactive Dating Key Concepts
What happens during radioactive decay?
What can be learned from radioactive dating?

16. 4.3 Radioactive Dating Key Terms
Atom
Element
Radioactive decay
Half-life

17. 4.3 Radioactive Dating Radioactive Decay
Atom –The smallest particle of an element.
Element – A type of matter in which all the atoms are the same.
During radioactive decay the atoms of one element break down to form atoms of another element.

18. 4.3 Radioactive Dating Determining Absolute Ages
Geologists use radioactive dating to determine the absolute ages of rocks.
Potassium-Argon Dating
Carbon-14 Dating
Radioactive Dating of Rock Layers

19. 4.4 The Geologic Time Scale Key Concepts
Why is the geologic time scale used to show Earth’s history?
What are the different units of the geologic time scale?

20. 4.4 The Geologic Time Scale Key Terms
Era
Period

21. 4.4 The Geologic Time Scale The Geologic Time Scale
The age of the Earth is so huge that this Geologic Time Scale is used to put the span into sequence past to present.
Era – The largest divisions (like seasons)
Paleozoic – Mesozoic – Cenozoic
Period – Divisions within Eras (like months)

22. 4.4 The Geologic Time Scale The Geologic Time Scale
Period – Divisions within Eras (like months)
ERA Paleozoic =
Cambrian – Ordovician – Silurian – Devonian – Carboniferous - Permian
ERA Mesozoic =
Triassic – Jurassic - Cretaceous
ERA Cenozoic =
Tertiary - Quaternary

23. 4.4 The Geologic Time Scale The Geologic Time Scale

24. 4.5 Early Earth Key Concepts & Terms
When did the Earth form?
How did Earth’s physical features develop during Precambrian Time?
What were early Precambrian organisms like?
KEY TERMS
Comet
Continental Drift

25. 4.5 Early Earth Planet Forms
Scientists hypothesize that Earth formed roughly 4.6 billion years ago.

26. 4.5 Early Earth Earth Takes Shape
Scientists believe that the planet began as a ball of dust, rock, and ice in space.
Gravity pulled the mass together
More mass = more gravity = more mass = more gravity until the area nearby was cleared.
The ball was struck repeatedly added mass and kinetic energy heated up the mass.
(NOTE: Find a video link)

27. 4.5 Early Earth Earth’s Surface Forms
During the first several hundred million years of Precambrian Time, the atmosphere, oceans, and continents began to form.

28. 4.6 Eras of Earth’s History Key Concepts
What were the major events in the Paleozoic Era?
What were the major events in the Mesozoic Era?
What were the major events in the Cenozioc Era>

29. 4.6 Eras of Earth’s History Key Terms
Invertebrate
Vertebrate
Amphibian
Reptile
Mass extinction
Mammal

30. 4.6 Eras of Earth’s History The Paleozoic Era
The Cambrian Explosion
Vertebrates arise
Life Reaches Land
The Carboniferous Period
Mass extinction ends the Paleozoic
The Supercontinent Pangaea

31. 4.6 Eras of Earth’s History Precambrian

32. 4.6 Eras of Earth’s History Cambrian Period

33. 4.6 Eras of Earth’s History Ordovician Period

34. 4.6 Eras of Earth’s History Silurian Period

35. 4.6 Eras of Earth’s History Devonian Period

36. 4.6 Eras of Earth’s History Caboniferous Period

37. 4.6 Eras of Earth’s History Permian Period

38. 4.6 Eras of Earth’s History Triassic Period

39. 4.6 Eras of Earth’s History Jurassic Period

40. 4.6 Eras of Earth’s History Creataceous Period

41. 4.6 Eras of Earth’s History Tertiary Period

42. 4.6 Eras of Earth’s History Quaternary Period