FOSSIL forgers may be about to meet their match. A geology student in the US
has devised a way to spot if different fragments of fossilised bone have been
cobbled together to make a fake.
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Infamous fakes include Piltdown Man, a combination of human and ape bones,
and the Archaeoraptor fake exposed last year that was a composite of a
bird body and dinosaur tail
(New 杏吧原创, 29 January 2000, p 12).
But Doreena Patrick of Temple University in Philadelphia has found a way to quickly
expose such forgeries. Her test uses a mass spectrometer to measure the
concentration ratios of rare earth elements such as lanthanum and lutetium.
Modern bones contain only parts per billion of the rare earths, but fossils
absorb rare earth elements from water seeping through the rock, accumulating in
parts per million. Although concentrations of individual rare earths may vary
between parts of the same fossil, such as dental enamel and the dense outer
layer of long bones, the ratios of rare-earth concentrations stay similar for
all the fossils in the same rock formation. Early tests by Patrick have already
shown that rare-earth ratios can easily spot fragments from different sources.