Topic: Absolute Dating Absolute Dating is the real, true age of the rock
Examples - Tree Rings
Varves Layers of sedimentary rock that were formed in a lake from season to season
Radioactive Dating -
Absolute DatingRadioactive elements decay steadily. -----
Examples Front of ESRT
Parent IsotopeDaughter Isotope
# of Half-LivesHalf-Life of Carbon-14Age of Rock (years old)% of Carbon Remaining% of Nitrogen0123456
Example of Half LifeYour rock contains 3 grams of C14 and 9 grams of N14. How old is your rock?
Example of Half LifeA sample of wood that originally contained 100 grams of carbon 14 now only contains 25 grams of carbon 14. Approximately how many years ago was this sample part of a living tree?-
Example of Half LifeA rock contains 5 grams of Uranium 238 and 35 grams of Lead 206. How old is the rock?-
Example of Half LifeA fossil contains 5 grams of carbon 14 and 75 grams of Nitrogen 14. How old is the fossil?-
Final Question:A rock containing Potassium 40 undergoes 3 half lives, what is the age of the rock?-
Topic: The Earlier Earth
Law of Uniformitarianism The present is the key to the past.-
Earth is a Dynamic and Evolving PlanetChanges in its surface
Origin of Our Solar SystemSolar nebula theory
Planetesimals have formed in the inner solar system, and large eddies of gas and dust remain far from the protosun.-Sun and Rotating Cloud
How old is the Earth?4,600,000,000 = -
An Early Earth-Heat sources:----
Earths DifferentiationEarly Earth -
Lighter silicates flowed up to form mantle and crust.Why?
Earlier Earth Atmosphere-
Exploring Geologic TimeWhat has been around for a long time to help geologist study the Earth?
Final Question: The geologic history of an area can best be inferred by studyingA) erosional processes affecting the areaB) plants and animals now living in the areaC) present climatic conditions of the areaD) bedrock compositions and rock structures in the area
*Images from left to right:Changes in its surfaceArtists rendition of how Earth is thought to have appeared about 4.6 billion years ago.Paleogeography of the world for the Late Cambrian Period.Apollo 17 view of Earth. Africa, Arabian Peninsula, Madagascar, Antarctica, South Atlantic Ocean , Indian Ocean.
Changes in lifePossible precursor of life: bacterium-like proteinoid.Reconstruction of Middle Devonian reef from the Great Lakes area Shown are corals, ammonoids, trilobites and brachiopods.Cretaceous Pteranodon.