A single-column extraction chemistry for isotope dilution U-Pb dating of carbonate

Abstract

U-Pb dating can provide age constraints on carbonate minerals from a wide range of geological settings. A major practical limitation, however, is the need for rapid and efficient extraction of Pb and U from large numbers of typically low-Pb (≤10 ng/g) calcite samples, while maintaining low blanks (∼10 pg Pb) and high Pb-U yields and purity. Here we describe a well-tested ion exchange procedure able to extract Pb and U from large (up to 200 mg) calcite samples using a single pass over a mini-column filled with small (∼0.1 ml) volumes of AG1-X8 anion exchange and Eichrom TRU-resins. This ‘stacked resin’ technique halves the time spent on elemental extractions and provides MC-ICPMS-ready Pb and..