Lynn Carter

We see really strong reflectors from underneath.

And we also see some evidence of subsurface topography.

So there's like a little hill here.

So we've been able to measure the thickness of this deposit.

And one of the things that we're interested in doing is trying to see what this,

topography is buried underneath these hills.

We can't do 3D imaging of this yet because we don't have enough data like at the poles, but that's what we're trying to go for and be able to sort of reconstruct the subsurface structure of these hills and see if that will tell us anything about how they formed.

We actually used MARSIS to look over this too.

So this is the one that's the long wavelength radar.

And this is the same area, so this is Amazonas Mensa again, and it sees the reflector that Sharad sees, but it also sees another set of reflectors that are even underneath that.

So using the radar data, we've been able to see that there were these episodes of volcanism that are buried underneath the volcanism that we can see.

So we have these stacked layers, and the character of these layers suggests that it's all pyroclastic deposits.

So you had these stacked pyroclastic deposits with probably some era where there was some erosion or something to create this middle layer.

And so we thought these were big hills to begin with, but it looks like there's even a lot more of that material than what we thought.

And on Mars, it's actually easier to get pyroclastic volcanism and ash deposits because the low pressure

lets the gas dissolve more easily than on the Earth.

So you can basically get explosive eruptions much more easily than you can on the Earth.

So there should be a lot of pyroclastic material.

But this is still bigger than any pyroclastic or volcanic deposit that we have on Earth.

And it probably was not all created in one volcanic eruption.