Why is carbon-14 dating not suitable for materials approximately one billion years old?

Carbon-14 dating is based on the principle of radioactive decay, where carbon-14, a radioactive isotope of carbon, slowly transforms into nitrogen-14 over time. The half-life of carbon-14 is around 5,730 years, meaning that after this period, half of the original amount of carbon-14 in a sample will have decayed. In materials that are approximately one billion years old, the time elapsed is vastly greater than the half-life of carbon-14.

After one billion years, the amount of carbon-14 would have decayed to a level that is effectively undetectable, rendering carbon-14 dating ineffective for those ancient materials. This inability to detect carbon-14 in such old samples is what makes this dating method unsuitable; there simply isn't enough of the isotope left to provide a reliable measurement. Therefore, the assertion that carbon-14 becomes undetectable after one billion years accurately reflects why it cannot be applied to such old materials.