Lynn Carter

We think what happens here might be that when it's warmer, for example, you preferentially remove some of this ice and you get a lag deposit that's just the dust that was in there.

Mars is very dusty, so there's always dust being deposited on here.

But if you had dust in the ice and then you just sublimate or evaporate some of that ice off,

then what you're left with is just this dusty layer.

And so you might have these dusty layers caused by these seasonal changes basically all the way through the cap.

And so we think that's what we're seeing in this case.

But it's pretty impressive to have this, to be able to see in sort of a real way what's been going on with Mars climate.

So that was one of the first things that we found.

But since then, we have almost complete coverage of the poles, because Mars or Constance orbiter is pretty old missions, over 10 years old.

So we have tracks that really densely cover both poles.

We see the poles a lot more often than the equator, because we're always going over the poles with the orbit.

So one of the kind of weird things that we found were these buried features in the ice cap.

Like the North Polar Cap especially has these spiral troughs.

You can see this weird spiraling pattern.

And nobody was really sure how that formed before.

But it's a key feature of this cap and I mean you can just look at it and it looks weird and no one was really sure what happened so people thought maybe there was a change in the deposition or something weird was happening.

So with Sherrod we went and looked at what these look like underground and so here some of the spiral troughs got marked.

So you can see this one and this image and this image are the same but this one's marked.

You can see one here, there's kind of one here, but what we noticed were that there were some that are actually buried like here that aren't expressed at the surface at all.

So we found buried spiral troughs.