Isochron rock dating is fatally flawed

[ardipithecus]

Originally posted by npetreley
Or so says this interesting article.

http://tccsa.freeservers.com/articles/isochrons2.html

Basically the article attacks isochons by mentioning mixing. Though I see that the article has been debunked already, let me put in my $0.02.

As anyone who has read the T.O. Isochron FAQ or has done the math of the isochron knows, the slope of the isochron must be positive. (Lines with positive slopes are ones that rise as one goes from left to right.) False isochrons created by mixing can have either a positive or a negative slope. Thus is mixing was a significant problem, one would expect that a great many isochron diagrams with negative slopes. This is not observed in the real world. While there are some cases of false isochrons created by mixing, it is an extremely rare occurence. Furthermore, as the T.O. FAQ mentions, there is a plot that reveals mixing. Thus the mixing claim is a completely false.

And then there is the problem of different isochron methods giving the same radiometric date. Mixing cannot explain that except trough unbelievable coincidence.

 

[ardipithecus]

Originally posted by LiveFreeOrDie
The fundamental problem with this article is that it is making an apples-to-oranges comparison. The homogeneity constraint on Rb/Sr dating refers to the two daughter isotopes 86Sr and 87Sr. There is NO requirement that the Rb/Sr ratios be homogeneous -- in fact some variation in Rb/Sr ratios is desired.

Actually, lets make that a bit for forcefully:

Some variation in Rb/Sr ratios is required.

If there was not variation in the Rb/Sr ratios, then the isochron diagram would be a single point. Since the date is obtained from a slope of a line, there needs to be more than one point and hense variation in the Rb/Sr ratios.

Of course if this did happen the test would simply be inconclusive and will not give a false date.

 

[ardipithecus]

Originally posted by randman
Do you mean LFOD's link to Talkorigins. Personally, I don't even bother with anyone that links to that site. If I wanted to hear spin from the likes of Carville, I'd watch Crossfire.

Well you have yet to actually document any spin in T.O. like that given by James Carville.

But a simple question. Do you post links and expect people to follow them? If we refused to follow them would you call it close-mindedness? And if we attacked your links without reading them, what would you say?

I am going to agree with the others. The reason why you will not bother to look at the T.O. FAQ is because you can't even even scratch it let alone refute it.