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.
In a series of published papers and manuscripts soon to be published, we present our analytical techniques in detail (Mortlock et al., 2005; Chiu et al., 2005a) and the geochemical (Cao et al., 2005) and geophysical (Chiu et al., 2005b, 2005c) explanations for the departure of radiocarbon dates from the true calendar ages and compare our results to other radiocarbon calibration data.
Over the past decade we have witnessed a remarkable development and proliferation of accelerator mass spectrometers; these instruments have reduced the counting time by a factor of 100 and reduced the sample size by a factor of 1000 compared to the classic B-counting systems.
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.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.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.Common materials for radiocarbon dating are: The radiocarbon formed in the upper atmosphere is mostly in the form of carbon dioxide. Because the carbon present in a plant comes from the atmosphere in this way, the radio of radiocarbon to stable carbon in the plant is virtually the same as that in the atmosphere.Plant eating animals (herbivores and omnivores) get their carbon by eating plants.As explained below, the radiocarbon date tells us when the organism was alive (not when the material was used).