This line of research is focused on the dating method of Uranium Series. The two isotopes of uranium, U-238 and U-235 decay to stable forms of lead, through a complex chain that includes the formation of thorium. With the recent advance mass spectrometric techniques, dating by the uranium series is most suitable for carbonate materials (speleothems and calcite concretions in general).
It is a technique of wide applicability for cave deposits, paleosoils and mollusc skeletons. It also involves a more complex and elaborate instrumentation. The recent development of multicollector mass spectrometry with inductively coupled plasma has meant a giant step in the field of Quaternary geocronometry.