The FINAL date - and confidence is very, very high

Lab Note #7
Jun 19, 2014
I heard back from the lab today. Got the final dates, with extremely high confidence.  

Here's their note to me.  I don't understand it completely, but it fits in with everything that I've read about Argon/Argon dating.  

The hornblende worked extremely well. Now you can place 100% confidence that although the plagioclase was discordant the Plateau we assigned is it is total agreement with the Hornblende.
Plagioclase Age:  16.71 +/- 0.09 Ma
Hornblende Age:  16.68 +/- 0.06 Ma

I'm interpreting this to say that the Hornblende age is the one to go with, because it's the most reliable.  Either way, the two methods are within about 30,000 years of each other (plus or minus).  

I'm going to have to find someone at UW to work with me so I understand the many spreadsheets of data that I have; 7 spreadsheets with multiple tabs is a bit overwhelming, and this is not my area of specialty - but I want to be able to defend myself with grace and confidence if need be.


16.68 +/- 0.06 Million Years.

Older than the oldest Grand Ronde Basalt, "R1", the closest known outcrop of which is 5 miles away (there is speculation that it never made it as far as my site).

This is just SO COOL!

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