What are the pros and cons of radioactive dating?
1 Answer
Pro radioactive dating gives an absolute age for the rocks dated.
Con radioactive dating can only be used to date fossils older than approximately 50,000 years old.
Explanation:
Pro The half life of radioactive substances are empirically determined. The ratio of the parent to daughter atoms can be used to determine an exact age given the assumptions that none of the original parent atoms have been eroded or lost during the time being calculated.
Con All radioactive dating except Carbon 14 are based on atoms found in igneous rocks. Fossils are almost never found in igneous rocks. So radioactive dating can not be used to directly date fossils.
The one exception is Carbon 14. However Carbon 14 has a relatively short half life so it cannot be used on fossils much older than 50,000 years which makes it useful for anthropology but not geo history. Also most fossils no longer contain Carbon they have been turned to stone.
Radioactive dating gives hope for an objective empirical method of determining the age of fossils. But because of the likely hood of erosion and lack of direct application to fossils it doesn't work very well.
