Lecture 8 Geology 110
Table of Contents
- Earth Materials as Time Keepers
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- Why study the ages of rocks?
- 7.1 How do you determine the order of events?
- 7.1 How do you determine the order of events?
- 7.2 How are geologic events placed in relative order?
- 7.2 How are geologic events placed in relative order?
- 7.2 How are geologic events placed in relative order?
- 7.2 How are geologic events placed in relative order?
- 7.2 How are geologic events placed in relative order?
- 7.2 How are geologic events placed in relative order?
- 7.3 How do geologists determine the relative ages of rocks in widely separated places?
- 7.3 How do geologists determine the relative ages of rocks in widely separated places?
- 7.3 How do geologists determine the relative ages of rocks in widely separated places?
- 7.3 How do geologists determine the relative ages of rocks in widely separated places?
- 7.3 How do geologists determine the relative ages of rocks in widely separated places?
- 7.3 How do geologists determine the relative ages of rocks in widely separated places?
- 7.4 How was the geologic time scale constructed?
- 7.4 How was the geologic time scale constructed?
- The Geologic Time Scale
- 7.4 How was the geologic time scale constructed?
- 7.4 How was the geologic time scale constructed?
- 7.5 How do you recognize gaps in the rock record?
- 7.5 How do you recognize gaps in the rock record?
- 7.5 How do you recognize gaps in the rock record?
- 7.5 How do you recognize gaps in the rock record?
- 7.6 How have scientists determined the age of Earth?
- 7.6 How have scientists determined the age of Earth?
- 7.6 How have scientists determined the age of Earth?
- 7.6 How have scientists determined the age of Earth?
- 7.6 How have scientists determined the age of Earth?
- 7.6 How have scientists determined the age of Earth?
- 7.6 How have scientists determined the age of Earth?
- 7.7 How is the absolute age of a rock determined?
- 7.7 How is the absolute age of a rock determined?
- 7.7 How is the absolute age of a rock determined?
- Validating the method
- Validating the method
- Applying the method
- 7.7 How is the absolute age of a rock determined?
- 7.7 How is the absolute age of a rock determined?
- Absolute and Relative Age Dating
- Combining Absolute and Relative Age Dating
- Age of Earth
- 7.7 How is the absolute age of a rock determined?
- 7.8 How do we know ... how to determine half-lives and decay rates?
- 7.8 How do we know ... how to determine half-lives and decay rates?
- 7.8 How do we know ... how to determine half-lives and decay rates?
- 7.9 How do you reconstruct geologic history with rocks?
- 7.9 How do you reconstruct geologic history with rocks?
- Reconstructing Geologic History
- Geologic History cross section
- 7.9 How do you reconstruct geologic history with rocks?
Text and Images from Slide
- 18th century geologists, including James Hutton, applied scientific observations and principles to conclude the rock record required an old Earth.
- Lord Kelvin used a concept model based on a cooling Earth which suggested an age of 20-40 million years.
- John Joly used a concept model based on back-calculating the time required to make Earth's ocean salty. His model suggested an age of 80-100 million years.
- Radioactivity was critical in determining the age of Earth. It provided an internal heating mechanism not considered by Kelvin. It also gave a means of measuring ages of rocks by decay of radioactive isotopes.
7.6 How have scientists determined the age of Earth?