1. Carbon Dating Used for determining the age of earth materials
Age of rocks, fossils
Every living organism on Earth has carbon
When organism dies, carbon remains but begins to break down at a predictable rate- half life
Half-life of carbon-14 is 5,730 years

2. How old is it?
Every 5,730 years the amount of carbon will reduce by half.
This means that no matter how old something is, the amount of carbon can get smaller and smaller but never go away.
If a fossil of a fish is found and scientists know it originally had 2g of carbon-14 and now only has g, how old is it?

3. If carbon is in all living things, it is in rocks and soil- decomposition.
Carbon dating is used to help estimate the age of the earth
But the oldest rocks are usually located at the bottom of a rock profile. Why?

4. Law of Superposition
Sediments or lava are deposited on top of the existing rocks or soil.
Those sediments are compacted to form new rock
New rock on top, old rock at bottom

5. Exceptions to the Law of Superposition
Faulting
Non-deposition
Intrusion- injection of lava from the mantle
Which layer is the oldest?
Which is the youngest?

6. Layers of the Earth
inner core - mass of solid iron with a temperature of F
outer core – liquid iron, responsible for our magnetic fields
mantle - slow moving molten rock or magma, F
crust - layer from 4-25 miles thick consisting of sand and rock

8. But wait, There’s more!
Lithosphere- crust and upper most part of mantle- tectonic plates move
Asthensophere- below lithosphere, upper part of mantle

9. Focus on the Mantle Liquid rock Heated by the core
Heat creates convection currents
Convection
currents make
tectonic plates
move

10. Mantle moves, Plates move

11. Continental vs. Oceanic Plates
Continental crust is less dense than oceanic crust
When continental plate collides with oceanic plate, oceanic will go under the continental and oceanic plate is subducted or recycled back into the mantle.
***See Plate Boundaries handout ***

12. When Plates Collide
Convergent Boundary- two continental plates collide forming mountains- Mt. Everest and Himalayan Mts
Subduction Zone- oceanic vs. continental or oceanic vs. oceanic- Ring of Fire, Mt. St. Helens, Mt. Vesuvius

13. Pull Apart Divergent Boundary- two plates pull apart Forms Mid-Ocean
Ridges
Mid-Atlantic Ridge-
Iceland Volcano

14. Sliding Past Each Other
Transform Boundary ↑↓- Creates Faults
Faults- cracks in the Earth where plates move past each other
San Andreas Fault, New Madrid Fault
EARTHQUAKES!

15. Earthquake! Fault- plate boundary
Focus- point inside the earth where earthquake begins
Epicenter- Point on SURFACE where earthquake begins

16. Earthquakes Release Energy
P-Wave- Primary Wave
S-Wave- Secondary Wave
Surface wave
Waves are longitudinal or transverse

17. Long Term Effects of Plate Movement
Continental drift
Slow and gradual movement of tectonic plates in the same direction
Alfred Wegener
Pangaea
Caused by convection currents in mantle

18. Day Night and More Rotation- spinning of Earth on axis
Revolution- orbit of Earth around the Sun
Earth’s axis is tilted 23.5 degrees
Altitude, longitude and latitude
Day and Night
Year
Seasons
Determines the temp and climate of a region