Extensive information about the geology of the Grand Canyon. Looks at some principles of geology evident there, forces that have shaped its geological features, how its valleys and canyons were formed, the characteristics of the Colorado...

An 81-page slideshow that looks at the principles of geology with respect to relative dating, at different concepts describing geological processes, at absolute age and radiometric dating, at the eons and eras in the geologic time scale,...

[Free Registration/Login may be required to access all resource tools.] How scientists have been able to determine the age of the Earth.

[Free Registration/Login may be required to access all resource tools.] How scientists have been able to determine the age of Earth.