Theoretically we can report dates as young as a single year, but the margin for error may be greater than the date reported. On the other hand, if the sample is too old, not enough C-14 may remain for an accurate measurement. This means that the upper limit of C-14 dating is currently around 50,000 years ago.
What are the limitations of C-14?
The practical upper limit is about 50,000 years, because so little C-14 remains after almost 9 half-lives that it may be hard to detect and obtain an accurate reading, regardless of the size of the sample. Fourth, the ratio of C-14 to C-12 in the atmosphere is not constant.
What are two limits to using Uranium 238 dating?
Uranium 238 is only found in igneous or volcanic rocks. So no fossils can be dated directly using U 238. Because of the huge differences in the half lives of Carbon 14 and Uranium238 they cannot be used together. Carbon 14 can only be used to date fossils of a very recent age.
What happens to the C 14 in a living organism what happens to the C 14 in a dead organism?
Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food. Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases.