U-Pb geochronology of speleothems by MC-ICPMS

Abstract

Building upon the work of Richards et al. [1998. U-Pb dating of a speleothem of Quaternary age. Geochimica et Cosmochimica Acta 62, 3683-3688], we have developed a method for precise dating of speleothems beyond the range of the U-Th technique using the U-Pb decay scheme. By coupling low-blank sample preparation procedures and multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) analytical methodologies developed for low-level Pb-isotope analysis, we find that, under ideal circumstances (radiogenic speleothems with very low common Pb), U-Pb dating of speleothems is not only possible, but also produces excellent age resolution-often comparable to or better than U-Th studies..