What are the four main subdivisions (columns) of the geologic time scale?

Geologic Time

Questions to Answer:

Define “Catastrophism” and “Uniformitarianism”. Who developed the principle of uniformitarianism according to the Chapter 11 voice-over presentation?

Distinguish between relative dating and numerical (absolute) dating of rock formations.

List the three common types of radioactive decay as described in the Chapter 11 voice-over presentation.

What are the four main subdivisions (columns) of the geologic time scale?