Now I was excited to finally put this together in a way that made sense. And lacking another geology person in the shop, I had to come up with a way to explain it to a person who I knew would be interested, but didn't really have the background to understand. The following is a semi-accurate paraphrasing of how I told the story.
Imagine you're cooking up a batch of pea soup in a pressure cooker, and the lid blows off. It coats your entire kitchen with a layer of the thick paste. That's the kind of ignimbrite I've seen before. Now imagine you're cooking up a really big batch of pea soup in a really big pressure cooker, but the lid doesn't blow off, the whole cooker explodes, covering the whole neighborhood with pea soup, fragments of dishes, window glass, drywall and building lumber. It's mostly pea soup, but it has all these fragments of other stuff that happened to get carried along with it. That's what this ignimbrite is.The lesson in all this is that it's perfectly okay to not know something, but if it bugs you, keep at it, and be watchful for clues... you never know when or where an answer that makes sense will pop out at you. This one has been an irritant for 2 1/2 years. Others have taken me decades. If it puzzles you, just puzzle it right back!
Photo unmodified. October 9, 2012. FlashEarth Location.