Protactinium-231 Dating of Carbonates by Thermal Ionization Mass Spectrometry: Implications for Quaternary Climate Change

Abstract

Measurement of protactinium-231 ( 231 Pa) in carbonates by thermal ionization mass spectroscopy yields 231 Pa ages that are more than 10 times more precise than those determined by decay counting. Carbonates between 10 and 250,000 years old can now be dated with 231 Pa methods. Barbados corals that have identical 231 Pa and thorium-230 ( 230 Th) ages indicate that the timing of sea level change over parts of the last glacial cycle is consistent with the predictions of the Astronomical Theory. Two Devils Hole calcite subsamples record identical 231 Pa and 230 Th ages, suggesting that the chronology of this climate record is accurate.