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.

147Sm/144Nd #1

147Sm/144Nd of the first point.

143Nd/144Nd #1

143Nd/144Nd of the first point.

147Sm/144Nd #2

147Sm/144Nd of the second point.

143Nd/144Nd #2

143Nd/144Nd of the second point.

Fit a two-point Sm-Nd isochron and convert its slope to an age using the Sm-147 decay constant. 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]

Slope

Isochron slope in 143Nd/144Nd per unit 147Sm/144Nd.

Initial 143Nd/144Nd

Initial 143Nd/144Nd from the intercept.

Age (yr)

Isochron age in years.

Age (Ma)

Isochron age in millions of years.

• 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.

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