Carbon dating hominids
When organisms die, the carbon-14 begins to decay at a known rate.Carbon-14 has a half-life of 5,730 years so dating is limited to between a few hundred and about 50,000 years. It is also important that samples for dating are collected carefully to ensure they have not been contaminated with more recent carbon.This number is usually written as a range, with plus or minus 40 years (1 standard deviation of error) and the theoretical absolute limit of this method is 80,000 years ago, although the practical limit is close to 50,000 years ago.Because the pool of radioactive carbon in the atmosphere (a result of bombardment of nitrogen by neutrons from cosmic radiation) has not been constant through time, calibration curves based on dendrochronology (tree ring dating) and glacial ice cores, are now used to adjust radiocarbon years to calendrical years.This also works with stone tools which are found abundantly at different sites and across long periods of time.
Working out how old archaeological remains are is a vital part of archaeology.
To determine the year age (absolute age) of an object, a number of chemical and radioactive techniques can be used.
Four main methods have been used in Willandra archaeology.
These strata are often most visible in canyons or gorges which are good sites to find and identify fossils.
Understanding the geologic history of an area and the different strata is important to interpreting and understanding archaeological findings.
The majority of chronometric dating methods are radiometric, which means they involve measuring the radioactive decay of a certain chemical isotope.