Almost halfway through our tour of OSU geology! We’re coming up on the Memorial Union now, and I hope you left yourself lots of time, because this is one of those places that a person could get completely lost in – and that’s just on the outside of the building.
Stop 11: Memorial Union, East End
Approach the black hole. It doesn’t look like a black hole, but it is sucking you in.
Walk to the east end. Put your nose up against the rock. You have now passed the event horizon…
This is the Salem Limestone. Indiana’s famous for it, ships it all over the place. Indiana, a long damned time ago (330 million years), used to be a lovely little tropical sea, with coral reefs and shellfish, and there might have been islands with white sand beaches nearby, and the only drawback to being there then is the fact that the invention of alcohol was a third of a billion years in the future… but still, I’d take lounging round there at that time over lounging round there now. Just because I was born there doesn’t mean I have to like it.
I do love its limestone, though.
Right. So here we have very shelly limestone – practically a coquina, although not that shelly. We know that things like crinoids generally live in happy little shallow seas, so we’re suspecting a marine environment. And we know there was some vigorous, although not intense, wave action – enough it produced shell fragments, but didn’t wash away all the lovely carbonate-rich mud. All of these things point to a near-shore environment in a shallow tropical sea, but if you look up, you will find your final bit of evidence.
Ba-dum-dum. And yes, I very nearly hit Lockwood when he hit me with that, but I laughed. It’s funny. Awful, but funny.
And very nearly true. Turns out there are sedimentary structures preserved in the stone that tell us about currents and storms and tides. Pretty amazing, eh? You can read all about it in David B. Williams’s wonderful Stories in Stone.
Next comes one of the most delicious staircases I’ve ever seen, although the builders made a big mistake…