Over time, carbon-14 decays radioactively and turns into nitrogen. Because of the short length of the carbon-14 half-life, carbon dating is only accurate for items that are thousands to tens of thousands of years old. Most rocks of interest are much older than this.

Why is carbon dating not used to date things over around 50000 years old?

Carbon dating also cannot be used on artifacts over about 50,000 years old. These artifacts have gone through many carbon-14 half-lives and the amount of carbon-14 remaining in them is miniscule and very difficult to detect.

Is carbon cycle used in absolute rock dating?

One of the most widely used and well-known absolute dating techniques is carbon-14 (or radiocarbon) dating, which is used to date organic remains. This is a radiometric technique, since it is based on radioactive decay.