Age is also a problem: Samples that are older than about 40,000 years are extremely difficult to date due to tiny levels of carbon-14. Over 60,000 years old, and they cant be dated at all.

Why cant carbon dating be used to measure the age of something as old as a dinosaur?

But carbon-14 dating wont work on dinosaur bones. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old. To determine the ages of these specimens, scientists need an isotope with a very long half-life.