Re: Isochrons

Bill Hamilton (hamilton@predator.cs.gmr.com)
Tue, 23 Apr 1996 08:40:04 -0400

At 3:48 PM 4/22/96 -0500, Steven Schimmrich wrote:
>Bill Hamilton wrote:
>
>> Steven Schimmrich wrote:
>>
>>> Well, if the data form an isochron, it's assumed that the system has been
>>> closed since isotopic resetting.

I wrote
>>
>> However, Davis Young points out in "Christianity and the age of the earth"
>> that there are some physical inspections that can be made to help ensure
>> that the rocks being dated have not been contaminated in some way. They
>> involved things like looking for cracks and signs of seepage into the rock
>> being dated.

Steve responded
>
> Exactly. I think I pointed this out several times in my post where I said
>that you have to look at the rocks petrographically (under the microscope) to
>look for evidence of alteration, metamorphism, etc. and you can't just grab
>a rock and isotopically date it being ignorant of the geologic setting.
>
Yes, you did. My response above was written and sent before I had finished
reading your note. I just didn't want any young-earth creationist jumping
to conclusions.

Bill Hamilton | Chassis & Vehicle Systems
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