Rant: I just hit 500 hours logged on a specific shale formation and I think everyone's wrong about it.

I've been mapping this shale unit in central Pennsylvania for a while now, and the standard field guide says it's basically uniform for about 80 miles. After logging my 500th hour of fieldwork, I'm convinced that's not true. I've found three distinct microfossil layers and a clear change in grain size that happens right near the town of Lock Haven. This means the depositional environment shifted way more than the textbooks say. It's not just one boring layer. Has anyone else done detailed work on this formation and found similar local changes?

2 comments

2 Comments

jake_dixon1mo ago

That's a really interesting find. A professor I had in grad school always said the published maps were just a good starting point. He talked about finding similar small changes in what were supposed to be uniform carbonate units out west. Your 500 hours in the field probably trumps a lot of the older survey work. Those microfossil layers sound like a solid clue that things were more complex locally. Makes you wonder what else the general guides are smoothing over.

robert641mo agoTop Commenter

Yeah, that feeling when the field work starts arguing with the textbooks is the best part of the job. @jake_dixon is right about the maps just being a start. I had a similar thing with a sandstone unit everyone said was massive and clean. After enough time staring at it, I found these thin, gritty layers full of plant bits that pointed to a whole series of small floods nobody had written about. Your microfossil layers near Lock Haven sound like the same deal, a clear signal everyone else drove past. Here's to the details that mess up the simple story.