"Doublespike" isotopic dating methodofleadisotopeisone of the dating ways of lead isotope, its aim is to correctmassdifferentiationeffect and enhance the precisionof measure.
By analysing the isotopic composition of hydrocarbon molecules from plant waxes of the period, he found what looks like a spike in the amount of recently non-biological carbon (which has a distinctive ratio of light isotopes to heavy ones), lasting between 10, 000 and 20, 000 years.