Robust chronological reconstruction for young speleothems using radiocarbon

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dc.contributor.authorHua, Qen_AU
dc.contributor.authorMcDonald, Jen_AU
dc.contributor.authorRedwood, Den_AU
dc.contributor.authorDrysdale, RNen_AU
dc.contributor.authorLee, Sen_AU
dc.contributor.authorFallon, SJen_AU
dc.contributor.authorHellstrom, JCen_AU
dc.date.accessioned2014-04-11T04:24:12Zen_AU
dc.date.available2014-04-11T04:24:12Zen_AU
dc.date.issued2012-12-01en_AU
dc.date.statistics2014-04-11en_AU
dc.description.abstractWe have studied two young speleothems, SC4 from Smiths Cave (Christmas Island, eastern Indian Ocean) and WM7 from Wollondilly Cave (Wombeyan caves, SE Australia). Attempts to date these speleothems by the Th/U method have proved unsuccessful with some age reversals for SC4 due to multiple sources of non-authigenic Th. This method has also resulted in imprecise ages for WM7 because of low U concentrations (<10 ppb) and consequently very low levels of authigenic Th-230 relative even to the very low levels of detrital Th-230 present. Here, we present an alternative method for reliable dating of these young speleothems using radiocarbon. Approximately 100 carbonate samples from SC4 and WM7 were analysed for C-14 by accelerator mass spectrometry (AMS). The AMS results indicate that bomb C-14 was evident in the youngest parts of both stalagmites. Two different approaches were used to estimate dead carbon fraction (DCF) values for these stalagmites for the pre-bomb period. For SC4, the DCF values were estimated based on the timing of C-14 dates for that period determined by high-resolution delta O-18 recorded in the speleothem, and the timing of the onset of bomb C-14. For WM7, a "maximum" range of pre-bomb DCF was determined. Chronologies of these speleothems were built based on a dense sequence of DCF-corrected ages using three different age-depth models: Clam (Classical method), and Bacon and OxCal (Bayesian statistical approach). Good agreement between these age-depth models were observed indicating that the top 170 mm of SC4 and the top 50 mm of WM7 grew during the past 550-750 years and 1360-1740 years, respectively. © 2012, Elsevier Ltd.en_AU
dc.identifier.citationHua, Q., McDonald, J., Redwood, D., Drysdale, R., Lee, S., Fallon, S., & Hellstrom, J. (2012). Robust chronological reconstruction for young speleothems using radiocarbon. Quaternary Geochronology, 14, 67-80. doi:10.1016/j.quageo.2012.04.017en_AU
dc.identifier.govdoc4780en_AU
dc.identifier.issn1871-1014en_AU
dc.identifier.journaltitleQuaternary Geochronologyen_AU
dc.identifier.pagination67-80en_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.quageo.2012.04.017en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/5420en_AU
dc.identifier.volume14en_AU
dc.language.isoenen_AU
dc.publisherElsevier Science Ltden_AU
dc.subjectCarbon 14en_AU
dc.subjectSoilsen_AU
dc.subjectBombsen_AU
dc.subjectClimatic changeen_AU
dc.subjectTree ringsen_AU
dc.subjectQuaternary perioden_AU
dc.titleRobust chronological reconstruction for young speleothems using radiocarbonen_AU
dc.typeJournal Articleen_AU
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