Question

Charcoal found deep in a layer of sediment in a cave is found to have an atomic ratio only 10% that of the radiocarbon age of the deep layer. What does this indicate about the age of the charcoal?

a) It is older than the radiocarbon age.
b) It is younger than the radiocarbon age.
c) It is equal to the radiocarbon age.
d) It is unrelated to the radiocarbon age.

Answer 1

Charcoal with only 10% of the expected carbon-14 content indicates that it is older than the radiocarbon age because the isotope greatly reduces over several half-lives.

Step-by-step explanation:

If charcoal found in a layer of sediment in a cave has an atomic ratio only 10% that of the radiocarbon age of the layer, this indicates that the charcoal is older than the radiocarbon age. Radioactive carbon-14 or 14C is used to determine the age of previously living things through a process called carbon dating.

This technique relies on the predictable decay of carbon-14, which has a half-life of 5730 years. Since the atomic ratio is at 10%, it suggests that multiple half-lives of carbon-14 have passed, significantly reducing the original amount of the isotope present in the charcoal.