Archaeology is all about the moment of discovery. One can follow the historical clues and look
for visible cues for likely places to find buried treasure troves of knowledge,
but the excitement comes when you dig and poke and brush and scrape away the earth
to – at long last – uproot a prize specimen, whether a fossilized microflora,
a whole skeleton of a heretofore unknown animal or something in between.
Almost since its inception, archaeology has embraced photography
and other imaging techniques to build up the banks of knowledge derived from each
finding, no matter how large or small. But until recently, archaeologists have not
known that they could look deeply into the fossilized record to find traces of the
chemicals left behind by once-living creatures.
Now, however, researchers using the Stanford Synchrotron Radiation
Lightsource (SSRL) in Menlo Park, Calif., have used intense x-rays to probe one
of the most famous of fossils, finding molecular clues to the biochemistry of the
animal.
The scientists discovered the chemical record deep inside a specimen
of Archaeopteryx, an animal that bridges the evolutionary gap between dinosaurs
and modern birds. The researchers include Phil Manning and Roy Wogelius of the University
of Manchester in the UK and Uwe Bergmann of the US Department of Energy’s
SLAC National Accelerator Laboratory, home of the SSRL.
Normal imaging techniques, including computed tomography, had
been used on the fossil since its discovery several years ago in Germany. Placing
the fossil under the bright beam of the SSRL, however, showed that the fossil was
more than bone and stone. The investigators found minute quantities of copper, zinc,
sulfur and phosphorus – all elements necessary for dinosaur health or feather
development in birds. Importantly, the concentrations of these chemicals differed
between the fossil and the rock within which it is embedded, proving that they are
not merely seeing material leached out of the stone but elements actually originating
with the Archaeopteryx.
The technique, if followed up by other archaeologists in future
projects, could provide very important supplementary information about the animals
that roamed the globe millions of years ago.