6533b7d9fe1ef96bd126cae6
RESEARCH PRODUCT
230Th/U-dating of a late Holocene low uranium speleothem from Cuba
Claudia FenstererJesús M. PajónDenis ScholzDenis ScholzDirk L. HoffmannAugusto Manginisubject
Accuracy and precisiongeographygeography.geographical_feature_categoryMineralogyThermal ionizationSpeleothemchemistry.chemical_elementStalagmiteUraniumMass spectrometrychemistryInductively coupled plasma mass spectrometryGeologyHolocenedescription
We present 22 U-series ages for a stalagmite from north-western Cuba based on multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and thermal ionisation mass spectrometry (TIMS). Our results reveal that the stalagmite continuously grew within the last ~1400a. Low uranium content of the sample and thus, extremely low 230Th concentrations limit the precision and accuracy of 230Th/U-dating by TIMS. Samples measured by MC-ICPMS show a high variability of 232Th content along the growth axis with some sections significantly affected by initial 230Th from a detrital phase. An a-priori bulk earth ratio for (238U/232Th) cannot be used to accurately account for this initial 230Th. Using an age model based on the 230Th/U ages determined on samples with low or negligible 232Th concentration, we find that the (238U/232Th) activity ratio of the detrital phase is an order of magnitude larger than the bulk earth value, indicating the importance of an accurately determined correction factor.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-03-01 | IOP Conference Series: Earth and Environmental Science |