Back in college, I would just grab any rock from a creek for my collection...

Now I spend a good hour looking at the layers in the bank first, ever since a trip to the Potomac River last fall. Seeing the clear contact between the graywacke and the shale made me realize the story is in the spot you pick it from. How do you guys decide where to collect a sample?

2 comments

2 Comments

fisher.rowan7d ago

It's all about the story for me now too. That context is EVERYTHING. I look for spots where the rock types change, or where the layers are bent or broken. A plain rock is just a rock, but one from a clear fault line tells a million-year-old story.

elliot_king7d ago

Read a cool article about how geologists can spot ancient earthquakes in those bent rock layers. They look for tiny mineral grains that got smashed and realigned under pressure. Makes you realize a quiet hillside could be a snapshot of pure chaos from way back.