NASA
Nasa: Planetary Geology
This unit teaches students about the forces that shape planets and help them to evolve. Lessons provide background information and assessments.
Other
Planetary Society: Relative and Absolute Ages in Histories of Earth and the Moon
A lengthy scholarly article that discusses the geologic time scale, its history of development, age-dating events that occurred in different eras, and how absolute and relative dating are used to assess the ages of the Earth and Moon....