From: Dawsonzhu@aol.com
Date: Fri Oct 03 2003 - 13:30:25 EDT
Allen Roy wrote:
> I think that most everyone also knows that when Rb/Sr radioisotope
> measurements were made of these rocks, contrary to what was expected, the Uinkaret
> lava flows actually measure and compute to be OLDER (~1.3 Billion years old)
> than the Cardenas Basalts (~1.1 Billion years old). This is a conundrum to any
> geologist -- Creationist or Evolutionist. All arguments about assumptions and
> justifications aside, it still remains a fact that EVERYONE discards and
> rejects the Rb/Sr computed ages for the Uinkaret lava flows as applying to when
> they flowed and crystallized. Although the methodology and technological
> processes were faithfully and precisely followed on rock samples from both
> sources, the dating for the Uinkaret is rejected while dates for the Cardenas are
> accepted. This comes to my point. Just because the process of isometric dating
> is done with great precision and great care, that does not automatically
> mean that the results are going to be accepted as valid. In many geological
> papers where isometric samples have been processed, there is usually a
> "discussion" about whether to accept or reject the ages so acquired. That choice comes
> about through factors other than the accuracy of the isometric process. In
> the case of the Uinkaret/Cardenas igneous rock, non-scientifically acquired
> data takes precedence over the scientifically (technologically?) acquired
> isometric data. It is strictly observation and logic concerning the law of
> superposition that shows that the Uinkaret must be younger than the Cardenas. This
> fact outweighs the scientific data acquired through the isometric dating
> process.
The first question I would ask is what kind of error bars should I expect
from Rb/Sr measurements. Is 50% error sometimes to be expected in
very old rocks? I'm not saying that's great if we can only expect this
kind of broad-side-of-a-barn estimate, but it would still provide at least
that level of objectivity to the issue. In astronomy, sometimes even
being several orders of magnitude off is still considered acceptable.
So it will also depend on what criteria is appropriate for a particular
kind of measurement. A ruler is unlikely to measure a micron sized object
accurately, but you could still say (objectively) that something is much
smaller
than a mm.
By Grace alone we proceed,
Wayne
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