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Radiocarbon dating calibration

In a recent study (*Bondevik et al., 2006), Reimer, the lead author of the Int Cal04 paper) and her colleagues retract the Cariaco calibration data in Int Cal04 data set and Int Cal04 calibration curve and inserted the floating tree ring data set in its place. P., Int Cal04 is mainly constructed from 14C dates of foraminiferas from Venezuela.s Cariaco basin that are corrected for a constant reservoir age of 405 years.

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We will update our calibration curve every year and publish the data within 12 months of the update.In our radiocarbon calibration paper (Fairbanks et al., 2005), we present paired C age determinations (Lawrence Livermore National Lab and Leibniz-Labor for Radiometric Dating and Isotope Research Christian-Albrechts University Kiel) that span the entire range of the radiocarbon dating technique and present a radiocarbon calibration curve based on a Bayesian statistical model with rigorous error estimations.Due to the importance of an accurate and precise radiocarbon calibration curve, we have measured many samples in duplicate and validated the quality of the samples by dating the older samples with redundant U dates.The Int Cal04 includes predominantly laminated sediments from the Cariaco Basin from 11,900 to 14,000 years BP along with coral data from numerous investigators of varying sample quality based on the reported presence of calcite in samples analyzed by some of the contributors.In contrast, our calibration program (Fairbanks et al., 2005; 2007) uses the 1382-ring floating tree ring data set from Kromer et al., (2004) for the time interval between 12,600 and 14,000 yrs BP anchored by our coral data set.To better serve the archeological community, we will also release the calibration data and access to our curve to Cal Pal at the same time we update our curve.

The curve will be updated every year on Jan 1 and versions are identified as Fairbanks followed by the month and year such as Fairbanks0107 for the upcoming version.

Our online radiocarbon calibration curve presented in this WEB site is a stand alone alternative to existing radiocarbon calibration curves that infer calendar ages based on interpolations and correlations of local climate proxies in deep-sea cores to the chronology of ice core proxies or assumptions about sedimentation rates.

Our calibration has the advantage that each data point in the calibration has a measured calendar age (U) and radiocarbon age with know errors that are independent from each other.

Another difference between the selections of Int Cal04 versus our calibration program is philosophical.

Seven years elapsed between publication of Int Cal98 and Int Cal04 although the majority of new data between 14,000 and 26,000 are from our laboratory.

Over this time interval, the Caricao data set used by Int Cal04 differs by more than 200 years from the tree ring and our coral calibration data.