Ancient dating methods
Ancient Egypt is a never ending source of inspiration for many of us – their myths , their history, and their art are so wonderful and enigmatic, that they have intrigued researchers for decades. An ancient Danish city has adopted a novel way to highlight its seafaring and plundering heritage by installing axe-wielding Viking road crossing signals. Archaeologists have made what could be a pivotal discovery in the populating of the Americas , challenging previous dominant theories of how the first people arrived. Ancient Greeks used cranes over a century earlier than currently believed, according to a new scientific paper.Walking through any modern city will confirm that as a species we have our heads fixed...The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay.and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of the Earth itself, and can also be used to date a wide range of natural and man-made materials.It has also been used to date many megafaunal finds.Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.At sites containing human and animal teeth, ESR can be used to determine how long the teeth have been in the ground, but finding teeth at an archaeological site is unusual, so this dating method is not as common as thermoluminescence or radiocarbon dating.ESR has been used to estimate the age of many archaeological finds, such as WLH3 (‘Mungo Man’), Homo floresiensis (‘The Hobbit’), and much older human ancestors like Homo ergaster and Homo neanderthalis.
Another possibility is spontaneous fission into two or more nuclides.
Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geologic time scale.
Among the best-known techniques are radiocarbon dating, potassium–argon dating and uranium–lead dating.
Isotopic systems that have been exploited for radiometric dating have half-lives ranging from only about 10 years (e.g., tritium) to over 100 billion years (e.g., samarium-147).
For most radioactive nuclides, the half-life depends solely on nuclear properties and is essentially a constant.