Re: Age dating question

"AllanL" <darknessfall@xxxxxxxxxxx> wrote in news:1156114257.419311.66540
@75g2000cwc.googlegroups.com:

Thanks for everyone's input on the other thread regarding mutation
traits in sexual reproduction; those are quite a bit of information and
it'll take some time for me to digest them. For reasons explained
previously, I have another question regarding the age dating for
objects or fossils. Now, I understand that the fact is there are
several methods for dating regarding, say, the age of the earth, or a
particular fossils, and these methods typically all agree with each
other on the results. These methods commonly involve the calculation of
measuring the amount/ratio of element A and element B, where element A
would naturally decay into B, thus by calculating the ratio and the
rate of decay, one calculate the age of the object in question.
(Ignoring the on a cosmo scale which uses other methods)

A rather popular arguement that keeps on repeating itself on various
boards is that such methods require a constant rate of decay with
knowledge of starting condition and no outside influence, etc. I saw an
analogy somewhere as follows: "A person (#1)walks into a room and

Isochron methods allow us to determine the starting condition. When a
rock is formed, the chemistry determines the ratios for each included
mineral. The ratios of interest are:

1. The ratio of radioactive element to daughter isotope.
2. The ratio of daughter isotope to non-radiogenic isotope (of the
daughter element).

1 is fixed at formation on a per mineral basis, that is it is different
for different minerals. 2 is fixed at formation across all minerals.

By measuring these two values at a later date, across a number of mineral
samples, if the materials are uncontaminated and truly cogenetic, we will
find that they plot on a line. If we make 1 the X-axis and 2 the Y-axis
of a graph, the X-intercept of this line will give the original value of
1. It's slope is proportional to the number of half-lives since the
minerals formed.

observes another person (#2) reading a book. The book opens to page 100
at the time of entrance of #1. One minute later, #2 turns the page to
101; another minute later, #2 turns the page to 102. #1 then conclude
that prior to #1 entering the room, #2 has been in the room for 99-100
minutes. Since (1) the person might not start at page 1, (2) the book

See above. We know what page the rock started on. We also know that the
forces required to change the decay rate would melt the rock and thus
remove any isochron.

might have pages with fewer/more content and thus require fewer/more
time to read, and (3) person #2 could be distracted by #1 somehow
during the observation, or there are some circumstances to help/hinder
#2 during the reading time previously, the method cannot provide a
reasonable analysis of #2's time in the room reading."

I am trying to find a suitable counter-arguement for this.

Learn the details of the isochron method.

Specifically, are there any way of determining the following to ensure
the decay-type of dating method?
1, the original composition of elements as starting condition;

Yes, the isochron method makes that determination as a part of the
method.

2, the rate does not change over time;

Rates have been changed experimentally. The process requires heating the
materials to a plasma. Clearly this has not happened since a currently-
available rock has formed.

3, the fact of observation and measurement, and the relevant conditions
during an object's life time, would not influence the results.

Some things can contaminate. Geologists pick their samples with this in
mind. So do creationist geologists, by the way, seeking samples that are
undatable and then dating them in order to perpetuate the lie that
radiometric dates don't work.

And yes, that is about as ethical as stealing your opponent's king in
chess and then declaring victory. And it should be given just as much
credence.


--
Dave Oldridge+
ICQ 1800667

.

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