Best isotope to use when dating very old samples
“Estimation of groundwater age will be very useful to calibrate existing groundwater flow models, which local authorities will be able to use for the sustainable management of water resources,” said Rim Trabelsi, Professor Assistant at the National School of Engineers of Sfax in Tunisia, who attended the meeting in Vienna.“We appreciate the IAEA’s support for sampling and analysis, and also look to develop our knowledge in the use of isotopes in water resources management through these training courses and meetings.” A fellow participant, Sibele Ezaki, a researcher at Secretariat for the Environment of the State of Sao Paulo in Brazil, is conducting a study to estimate the date of groundwaters in the Tubarao aquifer in Sao Paulo State.
“The IAEA Isotopic Hydrology Laboratory is hoping to help more researchers who need support for sampling and analysis of helium and krypton to ensure data integrity and consistency,” said Matsumoto.
There are three carbon isotopes that occur as part of the Earth's natural processes; these are carbon-12, carbon-13 and carbon-14.
The unstable nature of carbon 14 (with a precise half-life that makes it easy to measure) means it is ideal as an absolute dating method.
It also has some applications in geology; its importance in dating organic materials cannot be underestimated enough.
In 1979, Desmond Clark said of the method “we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation” (3).