Let's try this again, here's the story on carbon dating...
[ Scientists say their key tool for dating ancient artefacts might be
wrong by 10,000
years, which could push back the timing of key
events in history and improve
understanding of climate change.
Their study could force a reappraisal of when
certain events occurred, notably in the
period when modern humans lived alongside
Neanderthals in Europe. It suggests that
modern humans might have lived in Europe for
longer than thought and that prehistoric
paintings recently found in the Chauvet cave, in
southern France, might be
38,000-years-old rather than the estimated 33,000
years.
An Anglo-American team found large variations in
levels of the carbon-14 isotope, used
as the basis of carbon dating, preserved in a 19in
stalagmite recovered from a
submerged cave in the Blue Holes of the Bahamas,
limestone caverns created when sea
levels were nearly 330ft lower than today.
These findings suggested dramatic changes in the
amount of radioactive carbon in
Earth's atmosphere during the last Ice Age, much
greater than previously thought,
probably as a result of changes in the strength of
the planet's magnetic field. The field
shields Earth from cosmic rays that create
carbon-14 in the atmosphere, altering levels
of the isotope during the past 45,000 years.
Dr David Richards of the School of Geographical
Sciences, University of Bristol, made
the study with colleagues in Arizona and
Minnesota. He said: "Beyond about 20,000
years ago there are some dramatic swings in
radiocarbon concentration, which means
the age offset between the radiocarbon age and
true calendar age can be up to 8,000
years."
Radiocarbon dating, which depends on the steady
decay of carbon-14, is less reliable if
an artefact is older than 16,000 years. But the
changes in radiocarbon, and dating,
fluctuate greatly up to 45,000 years, the limit of
the study. ]
Source link.
http://www.telegraph.co.uk/et?ac=001851641145319&rtmo=rQrDEbmX&atmo=rr
rrrrrq&pg=/et/01/6/30/wdate30.html