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Professor Dave Explains
Methods of Dating the Earth Part 1: Relative Dating
We've learned about all the enormous time spans that describe the billions of years in Earth's history, but how did we arrive at these dates? How can we know the age of the Earth? Let's learn about some dating methods, starting with...
Bozeman Science
Bozeman Science: Law of Superposition
Mr. Andersen explains the law of superposition and the principle of original horizontality. He uses an animation to explain how rock layers can accumulate over time. [6:21]
Incorporated Research Institutions for Seismology
Iris: Stratigraphy: Geologic History of a Region in Cross Section
Rocks may be created in layers, but those layers do not always stay in the form or location where they were created. Find out about the forces that can change rock layers that help tell the story of the Earth in that location.