7. What are some of the factors that challenge the precision of measuring geological time?

Answer 1

Inconsistencies in the thicknesses of the layers of rock being measured - from a few inches to a hundred feet?
Also vertical trees "growing" through "millions of years" of rock layers....
Old earth rocks are often carbon dated at younger earth ages than surface rocks - depending on their composition.
similar fossils supposedly indigenous to a certain layer of rock are sometimes found in different geologic strata.

Answer 2

The biggest challenge is incompetent scientists who drifted through school by getting answers from other people instead of learning the subject, but who were still able to get a job somehow. The next biggest is competent scientist having to take time out of doing the work to explain that Creationist Fundie religious zealots use a lot of dishonest techniques to make it sound like there is some big controversy being hidden in science that gives their mythical magic story some type of credibility to say the Earth is just 6000 years old according to the total you get when you add together the age of some of the men in the Bible, most of whom had well over 500 birthdays, had talking snakes and donkeys, and rode around on magic flying carpets. Yeah, right, that's more accurate than carbon dating.

Answer 3

the BIG one is that no one was around to document it! So we use methods like carbon dating, identification of fossils, etc. to help narrow down the approximation, but the geologic time scale is done on a large scale (eras) because we simply cannot get more specific.

Answer 4

the flux capacitor