However, the methods must be used with care -- and one should be cautious about investing much confidence in the resulting age...

especially in absence of cross-checks by different methods, or if presented without sufficient information to judge the context in which it was obtained.

Dating ml-89Dating ml-50Dating ml-55

C by the Liquid Scintillation (LS) counting method.

In the 1940's, Broser and Kallman (1947) discovered that certain organic compounds (scintillators) fluoresced when exposed to ionising radiation.

A more detailed report can be found in Polach (1987).

Discussion on the LS method can be broken down into a number of topics : counting liquid, counting vials, and the LSC method, including counting instrumentation and potential problems associated with measurement of beta (ß)-decay by LS counting.

Later, this date was confirmed by two other dating methods (paleomagnetism and fission tracks), and was widely accepted.

Then Richard Leakey found a skull (called KNM-ER 1470) the KBS tuff, a skull that looked far too modern to be 3 million years old.

They said the sample was contaminated with excess argon.

Using new samples of feldspar and pumice they ‘reliably dated’ the tuff at 2.61 million years, which agreed nicely.

The details outlined below describe the procedures used in the Waikato laboratory to give the reader some idea of how the chemical conversions may be carried out.

The carbon is first oxidised to CO, either by acid hydrolysis (for carbonates), or combustion in an oxygen stream or combustion bomb (for organic materials).

On board are a dead man and a living baby, who they raise as their own and name Lucy.