Flaws in dating the earth as ancient

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Flaws in dating the earth as ancient

http://www.answersingenesis.org/creation/v18/i1/earth.asp

by Alexander R. Williams

In 1986 the world's leading science journal, Nature, announced that
the most ancient rock crystals on earth, according to isotope dating
methods, are 4.3 billion years old and come from Jack Hills in Western
Australia.

W. Compston and R.T. Pidgeon (Nature 321:766–769, 1986) obtained 140
zircon crystals from a single rock unit and subjected them to
uranium/uranium concordia (U/U)1 and uranium/thorium concordia (U/Th)2
dating methods. One crystal showed a U/U date of 4.3 billion years,
and the authors therefore claimed it to be the oldest rock crystal yet
discovered.

A serious problem here is that all 140 crystals from the same rock
unit gave statistically valid information about that rock unit.3 No
statistician could ever condone a method which selected one value and
discarded all the other 139. In fact, the other 139 crystals show such
a confusion of information that a statistician could only conclude
that no sensible dates could be extracted from the data.

A further problem is that the 4.3 billion-year-old zircon, dated
according to the U/U method, was identified by the U/Th method to be
undatable. An unbiased observer would be forced to admit that this
contradiction prevents any conclusion as to the age of the crystal.
But these authors reached their conclusion by ignoring the
contradictory data! If a scientist in any other field did this he
would never be allowed to publish it. Yet here we have it condoned by
the top scientific journal in the world.

This is not an isolated case. I selected it because it was identified
by the journal editors as a significant advance in knowledge. Another
example is the work of F.A. Podosek, J. Pier, O. Nitoh, S. Zashu, and
M. Ozima (Nature 334:607–609, 1988). They found what might have been
the world's oldest rock crystals, but unfortunately they were too old!

They extracted diamonds from rocks in Zaire and found by the
potassium-argon method that they (the diamonds) were six billion years
old. But the earth is supposed to be only 4.5 billion years old. So
Podosek and friends decided they must be wrong. They admitted,
however, that if the date had not been contradicted by the ‘known' age
of the earth, they would have accepted it as valid.

This clearly shows two fundamental flaws in long-age isotope dating.

First, the dates are readily discarded if they do not fit the
preconceived notions of the experimenter. Such a practice is not
acceptable in any other field of science because it destroys the
objectivity upon which science has built its reputation. Isotope
dating is therefore not the objective, absolute dating method it is
often claimed to be.

Second, it is impossible to tell, from the isotope information alone,
when the dates are right and when they are wrong.

When I presented this and similar criticisms of isotope dating to a
gathering of the Lucas Heights Scientific Society (Sydney, Australia)
in 1989, the only response that came from the chief of the division
responsible for isotope dating at the Australian Nuclear Science and
Technology Organization was the question, ‘Do you have a better dating
method?'

I said ‘No', and he appeared to be satisfied that if there are no
better methods of dating, then these are good enough. But can you ride
a bicycle into the past simply because no one else has a better
time-machine? Of course not. In the same way it is absurd to argue
that an inadequate method is adequate because nothing better is
available.4

References and notes

1. Uranium/uranium concordia—this method involves graphically
comparing the 238U/206Pb ratio with the 235U/207Pb ratio. Return to
text.

2. Uranium/thorium concordia—in this method the 238U/206Pb ratio is
graphically compared with the 232Th/203Pb ratio. Return to text.

3. The rock unit involved is a metamorphosed sandstone (quartzite)
in which the zircon crystals represent grains eroded from source rocks
(e.g. granites) and deposited with the sand. Thus the ‘ages' of the
zircon crystals represent the ‘age' of the source rock(s) and not the
‘age' of the quartzite. Return to text.

4. Further details of these examples can be found in my fuller
technical article on this subject in the Creation Ex Nihilo Technical
Journal 6(1):2–5, 1992. Return to text.
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