1. EARTH’S HISTORY- the guiding Rules

2. Unit Objectives: What you need to know
Guiding Rules to understanding the age of the Earth and the differenced between absolute and relative time
Understand how fossils form
Understand geologic time,
Recognize common organisms from the 4 geologic eras

3. Principle of Uniformitariasm
What happens now (the present) also happened in the past
Plate tectonics
Erosion
Deposition
Volcanism

4. Principle of superposition
Each sedimentary rock layer is put down in an undisturbed sequence
The oldest layers are on the bottom
The youngest layers are on the top

5. Principle of Faunal Succession
sedimentary rock layers contain fossils of plants and animals
these fossils succeed each other vertically (like the principle of superposition)
Oldest fossils in the bottom sedimentary rock layers youngest fossil layers in the top sedimentary rock layers
for example -A fossilized dinosaur bone will never be found in the same stratum as a fossilized trilobites

6. Relative Dating Techniques
Relative dating places events or rocks in their sequence of occurrence.
Oldest layers of sedimentary rock and fossils on the bottom youngest layers of sedimentary rock and fossils on the top

7. Crush unweathered
rock sample
Absolute dating/radiometric dating places events or rocks at a specific time.
Separate minerals
Run minerals through a mass spectrometer

8.
REVIEW