Geologic map of past eras of earth's history? O__O?

Question

Scientists have used a combination of relative dating and absolute dating techniques to create the__________, the "map" of past eras of earth's history.

I'm thinking either fossil record or geologic time scale.

Gah. X_X

My brain is going to explode.

Answer 1

1) geological time scale....they dont create the fossil record the fossil record is there....they can date fossils using the record and the layers around them....

2) 3 half lives.  If each half life is 12 million years then there are 3 half lives in 36my