Noun
Wetherill diagram (plural Wetherill diagrams)
(geology, geochronology) A type of concordia diagram, used in the context of uranium–lead dating, whose axes are the ratios Pb/U and Pb/Pb.
The "x" and "y" axes of the Wetherill diagram are the quantities of the respective end (lead) isotopes of the actinium series and uranium series decay chains, each adjusted and expressed as a ratio to the amount remaining of the corresponding start (uranium) isotope.
In the Wetherill diagram, no isotope is found on both axes, allowing the two decay schemes to be evaluated independently.