The trouble is that after 40,000 years there is under 1% of the original C-14 left, and it becomes too hard to measure it accurately.This isn't a fundamental limit as more accurate measurements could go further back, but at some point you'd simply run out of C-14 atoms.With our current kit 40-50K years is about the limit.Many people assume that rocks are dated at “millions of years” based on radiocarbon (carbon-14) dating. The most well-known of all the radiometric dating methods is radiocarbon dating.CARBON-14 IS ABSORBED (Figure 1b): Plants absorb this carbon-14 during photosynthesis.When animals eat the plants, the carbon-14 enters their bodies.So, if you're trying to use his to date dinosaurs, just stop. For an example, when they tried to get the carbon dating for presence of Aboriginal people in Australia they get to the number 40,000. Why is that 40,000 years limit for carbon dating methods?
Carbon-14 only works for things between 3 and 40 thousand years old. Carbon dating is based on an isotope of carbon, carbon 14, that's unstable. We breathe in carbon dioxide, we eat carbon, we take in carbon and so our bodies continually renewing our supply of carbon 14.Well, we're going to use exactly the same equation.So we'll say alright, the amount at 10,000 is equal to the initial amount that I started with 1.3 times 10 to the -12 times a half to the 10,000 divided by 5700. And when you do so, you'll end up with 0.385 times 10 to the -12. Since the atmosphere is composed of about 78% nitrogen,2 a lot of radiocarbon atoms are produced—in total about 16.5 pounds (7.5 kg) per year.These rapidly combine with oxygen atoms (the second most abundant element in the atmosphere, at 21%) to form carbon dioxide (CO).