Thanks for the update. Great stuff. I wish I had had had access to "electron microprobe analysis" when I was trying to figure out the identity/provenience of the obsidian specimens I had found in a number of Northern Yukon sites, many years ago, and, especially the nature of something I have called THTC (Tertiary Hill Tuffaceous Clinker) which I tracked in hundreds of sites ranging from northern Alberta to north-central Alaska. In those day, all I could count on was microscopic examination of thin slides and neutron activation analyse (NAA).
Good luck with your work and keep us informed.
Jacques
