But the important thing is, what's really remarkable about this is that
we published a paper in late January of 2014.
And in the same issue of Science the opportunity
science team reported a second occurrence of concretions in a much older rock.
At, at Meridiani Planum and now what is remarkable about this is that we
have explored three very different terrains on Mars that all involve
the activity of water and each of them has resulted in the formation of concretions.
Now, I can tell you that if you get let out of a helicopter almost any place on
Earth where you find sedimentary rocks that once formed in the presence of water,
we usually don't find concretions.
Concretions are cool and
rock hounds collect them because they're actually rather uncommon.
So the fact that we're three out of three on Mars is probably telling us
something and
we don't know what that means yet but it's an interesting trend that we've noticed.
And then we've got veins and fractures that cross cut the rocks and
they're filled with all kinds of hydrated minerals so.
We see calcium sulfate filling these minerals and
clay minerals as well which is one of the things that we were after.
Okay. So here's what these rocks look like and
these bumps and pits and
spires you can see them there raised up creating little tiny shadows.
And, and those are the concretions,
those little bumps that spick, stick out of the rock.
And then the rock is cross cut by these later fractures and
this looks like something you'd see in a mining district.
The rock's all fractured up.
You know that fluids flu, flowed through the rock later, and so this is yet another
phase of, of, of water, evidence of water that once flowed through the rock.
But this time, instead of making clay, the water made sulfate minerals.
But not the kind of sulfate minerals that form in acidic environments.
We think the kind of sulfate minerals that formed in pH neutral environments.
So the time came to drill and we did that.
And on the right, you can see the hole that Curiosity drilled in 2013 and
you can see the, the way that Opportunity ten years earlier.
It has a tool called the rock abrasion tool, the RAT, and
it grinds into the rock.
And we get down a millimeter.
It's enough to just take the veneer off the rock.
But what you see going on there is, is something that, that geologists do in,
in mineralogy lab called a streak test, where we take a, a white porcelain
plate and you take a rock that you think might have iron oxide in it,.
And if you scratch it across it, it makes a red streak.
And so when we ground up this rock we created all this fine powder and
we were amazed when it came back and it was red.
Because from orbit we had seen the signature for hematite and even before we
used the Mössbauer Spectrometer, just looking at the color all the geologists
knew there was hematite in this rock and we had found what we were looking for.
We kind of had the same experience when we drilled the hole and
the Sheepbed mudstone with curiosity and the powder came out.
The minute we saw this picture,
we knew we had something very different from what we had found at Opportunity.
Insto, instead of seeing the red color that's typical of the highly oxidized
state of the planet today and all the iron is in the Fe+++
valence, what we see instead is a rock that has a grey color,
which tells us if there is iron in there, it can't be all oxidized.
And indeed, when we did get the mineralogy in there,
we found out that iron was not present in hematite.
It was present in magnetite which is a mixture of Fe++ and Fe+++.
So that was good for us because we knew that we had not only found
an ancient aquean, aqueous environment.
It was, we also knew it was a lake.
And we also knew that this was the kind of lake where there was reducing conditions,
which really neat to see because that's important for planetary habitability.
Okay, so, then we take the powder and we feed it into our instruments.
And here is just a sample of the kind of data that we get.
And this is data that comes from the quadrupole mass spectrometer.
So they, we basically take the rock and we heat it up, as you can see here.
It basically gets up to about 900, 950 degrees.
It's Fahrenheit here because it's, I used this for general public.
And we heat that rock up and what it does is it kicks out all of the volatiles and
so the quadrupole mass spectrometer signal is on the y axis.
And what you could see as we heat it up,
the first thing that happens is we start to generate some water.
And pretty much concurrent with the generation of water, we see CO2 go up.
And we see that we're producing oxygen.
And then oxygen kind of peaks out quickly and then drops out.
Then carbon dioxide peaks after that and then begins to drop out.
And then water is produced and
then it begins to drop out but then the water comes back again.
And, and where the line goes from water to the spectrum,
you can see a, a smaller peak there that comes in.
And that converts to about 850 degrees centigrade.
And it turns out if you take clay minerals in the lab and
you heat them up, the interware waters in the clay minerals will kick out
at about 800 degrees centigrade.
So that's the expression of,
of the water coming off the rock from the clay minerals that we
confirmed that were there with the x-ray diffraction unit that we had as well.
The other cool thing that we see are two forms of sulfur.
