Mechanisms of collagen racemization in fossil bones: Application to absolute dating

Ages obtained by the measurement of amino acid racemization have generated controversy about the validity of this method.Experimental kinetics show that chemical racemization of bone collagen begins above 40°C. In a natural environment fossil bones are subjected to another mechanism, ‘spontaneous racemization’. A new methodology yields coherent results with fossil bones dated between ca. 50 ka BP and present, without any need of a preliminary calibration.