Same thing happened with Mt St Helens 1980 eruption. A pyroclastic flow carved out a huge canyon (referred to by many as a mini grand canyon) in hours and hydrological sorting occurred and formed the typical strata layering we see in other places claimed to be millions of years old, in a day or two.
The difference is that we were around to see it created and KNOW it took an extremely short period of time to come about. If we hadn’t the geologists would be pointing to it as being millions of years old.
I had to respond to your post. I heard that it’s been named “engineers canyon” but I can’t find any info.
I’m glad I’m not the only one to have learned of it though
That's where I collect all sorts of rocks for my rock garden.
Last time this area was a volcanic intrusion of any kind was several billion years ago. Still, there was a gigantic meteor hit the continental margin out here near the DELMARVA and that left a layered uplift of chunks ~ just like any impact crater ~ you can still make out the outlines if you know what you're looking for.
In between "Snowball" and "meteor" this was a chunk of North Africa. You find rocks typical of the region in Morocco.