Why is radiocarbon dating only rarely applied in geological work?

Answer 1

Radiocarbon dating can only be used to determine the age of objects that were once alive, such as fossilized bones or plants. It is of no use in dating geological formations that do not contain some remains of formerly living substances.

Carbon atoms are contained in most cells of all living things on Earth. Most carbon atoms (98.89 percent) are called carbon-12 because they have 6 neutrons and 6 protons in their nuclei. Most of the remaining atoms (1.11 percent) have 7 neutrons along with their 6 protons and are called carbon-13 atoms, but a very small quantity (called a trace amount) of carbon atoms have 8 neutrons and 6 protons. These and are called carbon-14 atoms.

Carbon-14 atoms are radioactive and are referred to as radiocarbon. They are unstable, and decay slowly by releasing electrons before evolving into nitrogen-14 atoms. A living organisms constantly absorbs carbon in its body systems by respiration and processing nutrients, and the amount of carbon-14 it contains remains fairly constant for as long as it lives. The carbon-14 decays without being replaced after the organism dies and half of the carbon-14 nuclei will disintegrate in about 5,730 years. The amount of carbon-14 that has disintegrated in a fossilized organism can be calculated and used for determining its age.