High-resolution U-Pb dating of an Early Pleistocene stalagmite from Corchia Cave (central Italy)

Recent developments in the uranium-lead (U-Pb) dating of speleothems have opened up new opportunities in palaeoclimate research. An important goal in this new frontier is to produce palaeoclimate records underpinned by precise and accurate age models, which together will increase the range of palaeoclimate questions that can be addressed by the speleothem research community. In this paper, we investigate the level of age-model precision that is achievable by applying high-resolution U-Pb dating of a stalagmite (CC8) from Corchia Cave (Italy) whose period of growth spans part of the Middle Pleistocene Transition (~970-810 ka). Focussing largely on the periods encompassing three glacial terminations, we carried out age sampling of CC8 at a density similar to that performed in many studies of younger (i.e. U-Th-dated) speleothems. Using a combination of Tera-Wasserburg isochron and model age approaches, coupled with age-depth modelling, our results show that age-model uncertainties of ~4 kyr are possible, equivalent to a precision of about 0.4%. At this level of precision palaeoclimate time series derived from speleothems of this age can be used to test hypotheses of orbital forcing. © 2012 Elsevier B.V.