Hello to all. I am a registered mechanical engineer with a solid background in metrology, material science, nuclear physics, and material phase transformations. I am currently employed in a manufacturing industry.
I don't have a big dog in this fight over the age of the earth but I would like to perform a sensitivity analysis on the potassium-argon methodology. I liken it to a glass-manufacturing problem where you have to deal with gasses trapped inside molten silica and atmospheric contamination driven by partial pressure.
As I see it I would like to evaluate the following variables for a sensitivity analysis, plugging into the radioactive decay formula:
1) How much atmospheric argon can be absorbed into molten silica over a long period of time at atmospheric pressure, and the temperature slightly above the melting point? I need this in ppm.
2) What is the range of K40 in current year magma samples in ppm and the corresponding A40 for the same samples with no atmospheric contamination?
I will use the decay formulas and any other assumptions or correction factors deemed appropriate, and excess argon. I'll use the following methodology from Bureau Laboratories:
http://geoinfo.nmt.edu/labs/argon/Methods/home.html
PS: I think the assumption of zero captive argon in a lava sample is not a good assumption. I do not know how much this affects the result but I will evaluate that as a sensitivity.
thanks to all