Absolute dating technology
A key point is that it is no longer necessary simply to accept one chemical determination of a rock’s age.
Age estimates can be cross-tested by using different isotope pairs.
It consists in comparing and matching two or more series of ring widths measured on different trees.
The partial overlap of sets of trees that died at different times allows the construction of average chronological sequences (courtesy Groupe de recherche en dendrochronologie historique; illustration C.
Repeated recalibrations and retests, using ever more sophisticated techniques and equipment, cannot shift that date. With modern, extremely precise, methods, error bars are often only 1% or so.
The fossil record is fundamental to an understanding of evolution.
For those researchers working in the field of human history, the chronology of events remains a major element of reflection.Results from different techniques, often measured in rival labs, continually confirm each other.