-----Original Message-----
From: Allen & Diane Roy
To: evolution
Sent: 5/3/00 11:27 PM
Subject: Re: How is this for an Anti-Evolutionist's use of quotes?
Thanks for following up on this. It seems to me that most of the
controversial issues about radiometric dating pertain to geology rather than
physics, but I'll have a guest speaker in my class tommorrow who thinks
otherwise! Anyway, you wrote the following at the beginning of your reply:
[I did confuse ratio and slope in my previous statement. The ratio
between the isotopes is assumed to be the same (homogenous) throughout
the mix and when plotted makes a slope of 0. In the case of Rb/Sr, the
claimed homogenous isotopes would be the 87Sr/86Sr ratio.
From the source mentioned below:
"Since D and Di are isotopes of the same element, they have identical
chemical properties*. Minerals may include varying quantities of that
element, but all will inherit the same D/Di ratio as the source
material. This results in an identical Y-value for the data points
representing each mineral (matching the Y-value of the source
material)."
This is saying that the ratio of D/Di is homogenous throughout the
magma.]
I know you disagree with this last claim, but can you send me some
references on magma concentrations that would be relevant to this issue? I
fear that this has been hashed out previously in this forum, so my apologies
go out to any subscribers who have been through it all already.
Jim Hofmann
http://nsmserver2.fullerton.edu/departments/chemistry/evolution_creation/web
/
This archive was generated by hypermail 2b29 : Thu May 04 2000 - 03:10:37 EDT