Logo of the Atomic Weights Commission Logo of the International Union of Pure and Applied Chemistry

    Calcium Isotope Materials

    Terrestrial isotopic-abundance variations for calcium are largest for biological systems, whereas inorganic materials exhibit only small calcium isotopic fractionations. Calcium-40 may be a poor choice for the denominator in the isotope ratio measurements because 40Ca is a product of 40K radioactive decay.


    δ44/42Ca Values of Reference Materials

    Name Material δ44/42CaSRM915a
    NIST SRM 915aCaCO3 0 ‰*
    NIST SRM 915CaCO3+0.085 ‰ **
    IAPSOseawater+0.88(11) ‰
    USGS EN-1shell from marine organism+0.35(9) ‰
    Name Material δ44/42CaSRM915a

    Footnotes      Back to Top
    * Exact value defining the δ44/42CaSRM915a scale.
    ** See the Assessment of international reference materials for isotope-ratio analysis for more details.
    Values in parenthesis are expanded (k = 2) uncertainties applicable to the last digits. The values listed in this table are compilation and are not necessarily CIAAW recommendations.

    Citation

    W.A. Brand et al
    Assessment of international reference materials for isotope-ratio analysis Pure and Applied Chemistry 86, 425-467 (2014)