High-precision mass-spectrometric uranium-series dating of cave deposits and implications for palaeoclimate studies

CALCITE deposits in caves, known as speleothem, can provide valuable palaeoenvironmental information1–4. In particular, because speleothem are deposited only in air-filled caves, gaps in deposition in coastal caves record high-stands of sea level. Here we report the use of isotope-dilution mass spectrometry to date speleothem by the uranium-series method. The use of mass spectrometry in uranium-series dating was first applied to corals5, and has greatly improved the precision of this dating method. The speleothem dated here—a flowstone from 15 m below modern sea level in a Bahamian cave—records changes in sea level over the past 280,000 years. The dated hiatuses in deposition indicate high sea-level stands that are in general agreement with data from deep-sea oxygen isotope stratigraphy6 and other estimates for the timing of high-stands and glacial minima1–3,7.