Dissolution methods for strontium isotope stratigraphy: whole rock analysis

The preparation of samples for strontium isotope stratigraphy (SIS) by whole rock dissolution results in contributions of Sr from contaminant phases as well as from the target carbonate phase. Here we highlight and quantify the errors in 87Sr/86Sr values that might result when calcium carbonate is dissolved using an inappropriate method. We report the variation in 87Sr/86Sr value of Sr released from four samples of differing calcite content and degrees of cementation, when subject to different methods of dissolution. We show that errors of up to ±0.000076 in 87Sr/86Sr, which correspond to errors of ±3.68 Ma in age, can be avoided by careful preleaching of the samples.