"Permineralization is a process of fossilization in which mineral deposits form internal casts of organisms."
The overflow at the hotsprings making casts of roots:
Now, I've this idea that if I hide a few stuffed dolls or animals under there I might in a few months have something curious for my desktop. My daughter and I tried it with one of her favorite stuffies at Big Hill Springs near Cochrane a couple of years ago - to no effect, wrong spot, but here, given how mineral-rich the waters are, might just yield better results.
More: https://en.wikipedia.org/wiki/Permineralization