Carbon dating is reliable within certain parameters but certainly not infallible.
When testing an object using radiocarbon dating, several factors have to be considered: First, carbon dating only works on matter that was once alive, and it only determines the approximate date of death for that sample.
Specifically, there are two types of carbon found in organic materials: carbon 12 (C-12) and carbon 14 (C-14).
It is imperative to remember that the material must have been alive at one point to absorb the carbon, meaning that carbon dating of rocks or other inorganic objects is nothing more than inaccurate guesswork.
This all changed in the 1940s when US chemist Willard Libby discovered that carbon-14, a radioactive isotope, could be used to date organic compounds."The radiocarbon dating technique may significantly underestimate the age of sediment for samples older than 30,000 years,” said the authors of the report from the Chinese Academy of Sciences and Germany’s Leibniz Institute for Applied Geophysics.“Thus it is necessary to pay [special] attention when using such old carbon data for palaeoclimatic or archaeological interpretations," they added.For example, a steel spearhead cannot be carbon dated, so archaeologists might perform testing on the wooden shaft it was attached to.This provides good information, but it only indicates how long ago that piece of wood was cut from a living tree.