Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

204Pb

Amount or signal of 204Pb.

206Pb

Amount or signal of 206Pb.

207Pb

Amount or signal of 207Pb.

208Pb

Amount or signal of 208Pb.

Normalize measured lead isotope amounts to 204Pb to obtain the standard 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

206Pb/204Pb

206Pb/204Pb ratio.

207Pb/204Pb

207Pb/204Pb ratio.

208Pb/204Pb

208Pb/204Pb ratio.

• Radiometric ages require the correct decay constants, isotopic ratios, standards, common-component correction, closure interpretation, initial composition, and analytical uncertainties. Disturbance, inheritance, diffusion, alteration, and model choice can make a calculated number differ from the geological event age.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• Geology Stable Isotope Delta Calculator

  Convert sample and standard isotope ratios into delta notation in permil relative to the standard.

• Geology Strontium Isotope Ratio Calculator

  Correct a measured 87Sr/86Sr ratio for instrumental mass bias by exponential-law normalization to 88Sr/86Sr = 8.375209.

• Geology U Pb Concordia Calculator

  Convert 206Pb/238U and 207Pb/235U ratios into concordia-style ages in Ma and their percent discordance.