For half of the radioisotopes of a certain kind to decay into its more stable isotope, the amount of time required is called the . Radiocarbon dating is typically used to date more recent objects like , cloth, wood, and plant fibers. rocks can't be dated accurately using isotopic dating because this rock type is formed through the sedimentation of different rocks and mineral fragments. Using the principle of faunal succession, scientists can determine the age of rocks by the embedded within them.