Wednesday, January 26, 2011
Montana, Chert, and the 1960s.
Two years ago, this rock really caught my eye while I was caving in the Madison Group of Montana.
First of all, there’s a nifty calcite or gypsum encrusted pocket, which looks much like a sparkly pothole…
(My assumption is that this formed as water seeped through the limestone into a small hole, and then crystallized on the hole’s walls.)
Then there’s the missing chunk, which gives a nice look at a crazy banded chert nodule.
If that chert nodule embodies John Lennon’s “Magical Mystery Tour” era, this nearby chert nodule is more Jackie Kennedy:
Way to keep it classy, chert.