That shelf collapse at the Burgess Shale dig site saved our fossils

I was up at the Walcott Quarry in BC last August, working a small section near the base. My hand went right through a loose shale layer and suddenly a whole shelf of rock slid down about 3 feet. Instead of losing everything, the slab cracked open and exposed a perfect Olenoides trilobite that was hidden inside. We bagged up the pieces and got it back to the lab in Calgary within 48 hours. The prep team said the fresh break actually made extraction way easier than if we'd tried to chisel it out. Has anyone else had a rock collapse turn into a lucky find like that?

3 comments

3 Comments

kim_nelson1mo ago

Wow, that's wild. Did the prep team say anything about pyrite damage on the fresh surface?

taylor821mo ago

I read pyrite can crack and crumble when exposed to humidity changes.

ericschmidt24d ago

Did anyone actually scope it with high magnification under controlled lighting? Pyrite decay usually shows micro-cracks before you see anything with the naked eye. I've seen specimens look fine on the surface but have that telltale white powdery mess hiding in the pores. What kind of prep method did they use on it, mechanical or chemical? That makes a big difference in whether the pyrite gets stressed during cleaning.