Today is Geologic Map Day, which is the closest holiday I could find that fits with this story: a geologic mystery in the record of Earth’s rock.

Or at least it should be there.


Our planet has a geologic record. Dig down deep enough into the layers of rock, and you can see evidence of what happened to the planet in different eras.

But there are gaps, known as uncomformities, where, for various reasons, there’s no record of what happened at all.

One of these is pretty big, about a billion years of geology missing.

Scientists call it the Great Uncomformity.

Now if you know geology, this is maybe not a huge surprise.

Earth is still very active, and over time things change, break apart, and move around; rocks are no exception.

What made these rocks change? That’s the mystery.

One theory was that long ago, during a very cold period known as Snowball Earth, glaciers moved around and more or less sanded all of the rock down.

But there’s evidence that the rock had been moving around before Snowball Earth even started.

Another theory is that it was a byproduct of the breakup of a supercontinent called Rodinia.

Tectonic activity pushed up a great deal of rock, which then over time it weathered away.

We don’t know for sure yet, so if you should happen to come across some rock that looks like it might explain where those billion years went, let someone know, ok?


Here are some more layers, but not geological ones, they’re more of the pepperjack variety.

It was on this day in 2001 that artist Cosimo Cavallaro made something unusual in Powell, Wyoming: he took large amounts of government surplus cheese, melted it down and sprayed it on a house, inside and outside.

The Wyoming Cheese House only stood for about two weeks, which those who smelled it say was definitely more than enough.

Maybe an apartment full of Gouda would’ve worked better?

Erasing a Billion Years of Geologic Time Across the Globe (Eos)

So, Uh, Where Did a Billion Years of the Geologic Record Go? (Popular Mechanics)

The Wyoming Cheese House (Weird Universe)

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Photo: an exposure of the Great Unconformity, west of Montezuma, New Mexico by Kent G. Budge – Own work, CC0, via Wikicommons