Archive for the ‘CRISM’ category

The 4th MSL Landing Site Workshop: Day 2 – Mawrth

September 29, 2010

Holy cow. Today was jam-packed with interesting stuff about Mawrth Vallis, Holden Crater and Eberswalde Crater! I took tons of notes, and I will try to use those to assemble a coherent picture of what was presented and discussed today. But if you’re too impatient to wait for me to work through those and post the more coherent summary, here are the notes in their raw and unedited form. Read them at your own risk, they’re full of jargon and typos and abbreviations! I’ll update that file tomorrow with tomorrow’s notes too.

In the meantime, I’ll start to translate those notes, starting with the first site on the table this morning: Mawrth Vallis. Joe Michalski started off the day with an overview of Mawrth emphasizing some of the key points about the landing site. Of course the obvious draw for Mawrth is that it is the best exposure of clay minerals on Mars. Clays form in wet environments and are good at trapping organics, so they are very desirable for MSL.  Joe (and subsequent speakers) also emphasized that Mawrth also has morphologic diversity and that it is an extremely old portion of the martian crust. Joe also pointed out that the fact that we see lots of clay minerals at Mawrth is not because Mawrth is unusual for early Mars. It’s much more likely that much of the early crust has similar minerals, but Mawrth is the best exposure.

The colors in this HiRISE image correspond to changes in the mineralogy. A similar stratigraphy is seen throughout Mawrth and the surrounding region.

The next talk was by Janice Bishop who summarized the mineral diversity in the site. She showed a bewildering number of spectra from Mawrth, and drove home the fact that the mineralogy observed occurs in the same stratigraphic order all over mawrth and all over much of the Arabia Terra region on Mars, supporting the idea that understanding Mawrth would teach us about a huge section of the planet. One of the interesting things that Janice and others showed is that these compositional layers are observed in some layered rock in the floor of Oyama crater, the huge crater to the west of the ellipse. This is interesting because it is thought that the rocks in the ellipse are older than Oyama, and obviously the rocks filling Oyama are younger. The fact that they show the same mineral stratigraphy suggests that the related alteration came after the physical deposition of the rocks.

After Janice’s talk, Eldar Noe Dobrea gave an overview of the morphology of the site. He showed a lot of nice HiRISE images of the site, and also gave examples of possible models for how the rocks at Mawrth were deposited, including impact ejecta, airfall, lakes and rivers, or an ocean. Eldar also showed a map of the ellipse that was completely peppered with markers indicating that he had observed layers. This was a contentious issue later in the day because Dawn Sumner, a sedimentary geologist who mostly studies the earth, gave a presentation saying that she didn’t see any convincing layering in the ellipse. Eldar also did something that John Grotzinger specifically said was very useful: he listed some of the thinks we don’t know about the site. In particular, we don’t know the origin of the clay-bearing rocks or the clays themselves. We also don’t know the amount of water that eroded the landscape or its pH, and we don’t know much about the dark unit that caps the stratigraphic sequence at Mawrth.

Another pretty HiRISE picture of Mawrth, showing some of the detailed surface textures.

Next up Damien Loizeau gave a nice talk about what we would do on the first day, month and year at Mawrth, and then Jean-Pierre Bibring gave a concluding presentation. Bibring emphasized the great age of the Mawrth Vallis rocks, pointing out that on earth rocks as old as Mawrth do not exist intact. All we have to work with are mineral grains preserved in younger rocks. So by going to mawrth we might actually learn a lot about Mars as well as about the conditions on very early earth.

Finally, as I mentioned above, Dawn Sumner gave a presentation based on her studies of the physical stratigraphy at Mawrth. She suggested that most of the features at Mawrth are due to cratering and that many of the “layers” are either fractures in the rock from impacts, or are not traceable for more than a few hundred meters at most. (Dawn also showed some very cool movies illustrating some of her points, using a new 3d visualization program that some of the other folks at UC Davis have developed called Crusta.)

After Dawn’s presentation there was a discussion period for Mawrth Vallis. One of the points that came up a few times is that the physical stratigraphy that Dawn was looking at is different from the mineral stratigraphy that seems to show more Al-rich clays above more Fe and Mg-bearing clays. There were also comments suggesting that it may actually be desirable to go to a complex ancient cratered surface precisely because it is confusing and there is no good terrestrial analog for us to study here  on Earth. Finally, there was a question about the abundance of clay minerals. In mixing models, Francois Poulet claims to see up to 60% clay minerals at Mawrth, based on OMEGA visible and near-IR data. But in thermal IR observations don’t see nearly that abundance. Steve Ruff, an expert in the thermal IR, said that TES does see some evidence of alteration but not at that sort of abundance. One expanation that he suggested is that the phyllosilicates might be poorly crystalline, so that VNIR observations see something but thermal IR doesn’t.

At the end of the discussion of Mawrth, I felt a lot better about the site than I did before going in. There is clearly a lot of good stuff to do there, and it has a couple of undeniable advantages: it is clearly the oldest site, and you get to land on your primary target. But I’m also concerned by what I hear from terrestrial geologists who are very concerned about how much Mawrth would actually tell us about the habitability of Mars. Yes, it has spectacular phyllosilicates, but it’s not clear that they would trap any organics since we don’t know what the depositional setting was. I think despite this uncertainty, if you polled the community, Mawrth would be one of the top two sites.


4th MSL Landing Site Workshop: Day 1

September 28, 2010

It has begun! Today was the first of a three day workshop in which the Mars science community (not just those directly involved in the MSL mission) gathers together and hashes out what we know and what we don’t know about the four finalist MSL landing sites.

For me the week actually started yesterday at the MSL team meeting, where we got lots of updates on the various aspects of the mission. Unfortunately, I don’t know how much of what I heard yesterday is safe to share with the world. Having been scolded before for sharing too much here I will just say that it’s really exciting to see all the pieces of the puzzle coming together.

Today, and for the rest of the week, everything is fair game to share with you, so I will do my best! Emily Lakdawalla will also be blogging parts of the meeting, so I’ll also point you to her posts about the meeting as they go up. In fact, you should go check out her introductory post right now. You might also want to refresh your memory about the four sites by reading this summary.

Today started off with some overview talks from the project manager Mike Watkins and project scientist John Grotzinger. Mike showed some awesome pictures of MSL (aka Curiosity), which is really starting to look like a rover. A jaw-droppingly huge rover. Watkins also had some nice analogies to go along with his pictures to convey just how huge Curiosity is. Remember the little Sojourner rover? It could just about use MSL’s wheels like hamster wheels. MSL is also really tall: its mast cameras could look Shaq straight in the eye, and its gigantic arm is so long it could almost dunk!

Curiosity is a huge machine. Note that the giant blob of instruments are not yet mounted on the arm in this photo.

I’m going to cheat and share a little of what I heard yesterday because this arm is just amazing and they used another good analogy. The instrument package at the end of the arm is huge: about 35 kg. You can picture this as something the size and weight of a lawn mower mounted on the end of a seven foot arm. The arm itself weighs 70 kg, and it is strong enough to dead lift that lawnmower even when the arm is fully extended. The MER rovers weigh 172 kg, the MSL arm weighs 105 kg. It. Is. Huge.

It finally sank in when I saw the presentations yesterday and today just how massive this rover is.

Anyway, back to today’s presentations. After the introduction, there were a series of talks about the preservation of biosignatures. One of the main take home points from these was that context is critically important for detecting and understanding biosignatures. If you understand the geology, you can try to look in places that maximize your chances of finding something. And then if you do find something, you can draw much better conclusions if you know its environment. This sort of argument makes a site like Eberswalde, where the story of a delta deposit in a crater lake is pretty well understood much more appealing than a site like Mawrth, where there are beautiful minerals, but we don’t really know the geologic story. Gale and Holden are both somewhere in between.

After biosignatures, there was a set of presentations about the mineralogy of the landing sites. This started with Frank Seelos unveiling the new and improved website containing a set of CRISM spectral images of the landing sites. You should go check them out: he specifically said that he would love it if we all melted his servers!

An example CRISM map of part of the Mawrth Vallis landing site, showing off the spectacular hydrated minerals in the site.

We also heard from Selby Cull, a graduate student who is attempting to use detailed models to figure out how much of a given mineral is in a sample based on its spectrum. Although it sounds straightforward, this is actually a phenomenally complex problem that planetary scientists have been grappling with for decades. It would be awesome if we could do this, but I’m skeptical.

After Selby, Ray Arvidson gave a talk about tying orbital to surface data at the MER Opportunity landing site and lessons learned that MSL should keep in mind. Bottom line (paraphrased) is that wherever you go, Mars is going to be more surprising and more interesting than we can imagine!

Finally Ralph Milliken shared his results on the compositions of the landing sites based on CRISM observations. It turns out that, using a subtle spectral parameter, you can estimate whether a given clay mineral detection is more or less “evolved” (where evolution could be due to burial or impacts among other things). Ralph also showed some exciting new stuff at Gale crater, including an example of a set of minerals visible in the southeastern portion of the Gale crater mound that looks very similar to the stack of mineral signatures seen near the landing ellipse.

A colorful map of the mineralogy at Gale Crater from Ralph Milliken. Greens are phyllosilicates, blue and magenta are sulfates, red is olivine, and orange is mixed sulfates and clays. The landing site is at the top center of this image, and the rover would ideally drive to the northwestern part of the mound, where there is lots of CRISM coverage.

Finally, after the mineralogy talks were over, we started hearing presentations about the specific landing sites. Gale was up first, and after Ken Edgett summarized the crater’s global and regional context along with some of what you can see within the crater, I gave my presentation showing off the interesting stuff that can be accessed in the ellipse and on a notional traverse up the lower portion of the mound. After me, my adviser Jim Bell presented about the composition of the stuff at Gale, and then finally Dawn Sumner gave a really interesting presentation about how to test some of our hypotheses at Gale Crater.

In the discussion of Gale the inevitable questions came up. One was: how old is the mound? The “problem” with answering that is that we think most of the terrain at Gale was buried and has since been exhumed again. That can totally throw off your estimated ages based on crater counting. The properties of the surface matter can too: some surfaces are hard and erosion resistant, so they tend to have more small craters than adjacent surfaces even if they are younger.The best estimate is that Gale crater formed at the end of the “noachian” period of martian history and the mound formed sometime in the late noachian to early hesperian. The exact timing of these epochs isn’t all that well constrained, but the noachian ended around 3.8 to 3.5 billion years ago, and it’s fair to say that Gale and its mound are about that old.

Three views of Gale crater. Top: An HRSC topographic map of the crater. Middle: A THEMIS thermal inertia map of the crater. Brighter areas are rockier, darker areas are dustier. Bottom: A THEMIS "decorrelation stretch" map, showing variations in color that can be roughly tied to composition. Pink is olivine, blue is dusty. Source: Anderson and Bell (2010)

We also talked about what it might mean if the whole mound is wind-blown grains. It’s certainly possible, but very difficult to tell from orbit. If the grains just filled up a dry crater, that might not be so good for habitability, but the mound is carved by canyons so we know there was flowing water well after the mound material had been deposited and turned to rock. On the other end of the spectrum, the mound might all be wind-blown grains, but those could have been trapped in the crater because it was full of water. As we heard earlier in the day, fresh basaltic sand plus water would provide the chemical energy necessary to support a pretty impressive chemolithoautotrophic (aka rock-eating) biomass.

There was also a lot of discussion of the evidence that Gale was actually buried. Someone asked whether there are any patches of layered material on the crater wall that match the mound layers. There aren’t, but I pointed out that there is a nice outlier of layered material hidden in the dune field 20km west of the mound itself. Ken Edgett reminded people (as he has been doing for 10+ years) that “this isn’t the mars you’re used to thinking about”, that entire regions have been buried and exhumed, and that this can happen without leaving a trace on the underlying surface. He also pointed to Henry crater as a Gale-sized example that does have a mound that matches with material on the walls. The question of why Gale seems to have preserved its huge mound of sediment, but all the other craters nearby did not keep theirs came up, and John Grant suggested that we do crater counting on the nearby craters which we know are older than Gale to see if their surfaces are anomalously young – as if they had been buried for a few billion years.

I also got the question of whether we should try to visit all of the cool stuff that I showed in the landing ellipse if the true goal of the mission is the mound. This is going to be the core question for this mission. At all the sites but Mawrth, you land on cool stuff but your main goal is outside the landing ellipse. The tradeoff between doing the “safe science” right away in the ellipse and sacrificing science early on to be able to make it to potentially more rewarding targets is going to be a huge part of the landing site discussion over the next few months. On Wednesday we are going to hear from some of the engineers and rover drivers about the engineering constraints on the mission, and then the Landing Site Working Group (a small subset of scientists that have been looking very closely at the landing site) will work with the rover drivers to identify the key targets at a given site and the key observations we want to make at those targets. From there, the engineers will come up with a set of potential traverses with detailed estimates of how long each will take. Since all of the sites are safe to land in, I think these estimates will play a major role in finally narrowing down to the final selection next spring.

AGU 2009 – Day 1

December 16, 2009

For those not familiar with the conference, the fall meeting of the American Geophysical Union is a terrifyingly, overwhelmingly large conference. Each year, something like 16,000 geoscientists descend on San Francisco to share their work. It is also one of the major planetary science conferences, so a lot of new results are first presented here.

Moscone Center in San Francisco. This building is filled with science at every fall AGU meeting.

This year, the first talks that I checked out on Monday were about radar observations of Mars. By sending radar waves from spacecraft to the surface and then recieving the reflected waves, we can learn a lot about Mars. In particular, since radar penetrates tens to hundreds of meters below the visible surface, it can reveal otherwise hidden structures. This has been especially successful at mapping the structure of the polar caps, because radar penetrates through ice quite well.

Roger Phillips gave a talk summarizing some of the results from the SHARAD radar instrument on MRO. Among other thers, SHARAD has found evidence that the spiral troughs in the north polar ice cap have migrated over time, as predicted many years ago by theoretical models. SHARAD has also found ancient buried canyons in the polar ice, which menas the ice caps have been around for quite a while. There are also some exiting new results implying that the material filling valleys in the Deuteronilus Mensae area is quite transparent to radar waves, and might in fact be something like glacier ice.

Image credits: NASA/ESA/JPL-Caltech/ASI/University of Rome/University of Washington St. Louis

After the radar talks, there were a whole bunch of presentations about aqueous alteration on Mars. One of the main lessons that I took away from those talks was that Mars is still a very confusing place. For example, Hap McSween used data from the Mars rovers and characterized typical soils at both landing sites. He found that the compositions of soils are roughly 70% unaltered material and 30% alteration products. He also showed that the soil compositions are quite similar between the two landing sites, which are on opposite sides of the planet, and that the unaltered portion of the soil is similar to the rocks at both sites.

However, the next talk by Josh Bandfield used orbital data and found that in general rocks on Mars have more of the mineral olivine than the soils. This is a somewhat different result than the rover data, and it might imply that rocks on Mars actually have more magnesium and iron than previously thought.

Other talks related to Mars alteration focused on “clay” and sulfate minerals detected on Mars. One that I found particularly interesting was by Paul Niles, who pointed out that Mars is an “obliquity-driven” planet. In other words, its tilt varies widely, and the Mars we see now is not typical. Niles suggested that during more typical periods, ice might have formed large layers at Mawrth Vallis, a location known for its strong hydrated mineral features. Melting at the base of that ice could have leached the rocks, explaining the presence of specific Al-bearing clay minerals.

Map of water-bearing minerals at Mawrth Vallis. Image credit: ESA/OMEGA team

Another interesting talk was by Itav Halevy, who took a look at how the presence of SO2 gas influences the formation of carbonate minerals. It turns out, even a tiny amount of SO2 gas (which is often released by volcanoes) can prefent the formation of CaCO3. If there is iron around, FeCO3 (the mineral siderite) forms instead. The implication is that sulfur minerals should form in different locations than clay minerals and siderite.

Continuing with the sulfur theme, Albert Yen talked about some results from the Spirit rover. He said that basically, if the rover had to get stuck, it picked a really fascinating place to do it! Based on the compositions measured, it turns out that there is too much sulfur in the soil to balance it out by assuming it is combined with other elements like Fe and Mg. That means there might be pure elemental sulfur mixed in with the soil, which would be consistent with hydrothermal activity!

My officemate and occasional contributor here at the Martian Chronicles, Briony Horgan, also gave a nice talk summarizing some of her recent work. For a long time there has been a question about the so-called “surface type 2” on mars. This surface type has higher than usual Si, but that could be due to a different type of lava, or alteration of the more common basalt seen elsewhere on Mars. Briony presented new evidence, based on the overall shape of the spectra of surface type 2 regions, that these areas might be due to a silica glass coating! This sort of coating could form when thin films of water from thawing ground ice altered the surface of sand grains, and would imply relatively recent alteration processes on mars.

Finally, the day ended with the Whipple prize lecture, which was unfortunately full of some misleading information about the history and status of Mars science. But that’s the topic for a future post.

New Google Mars

February 2, 2009

Google Earth’s latest edition was just released and guess what? It has a Mars setting! There was a way to overlay Mars data on the Earth globe in previous versions, but now that’s no longer necessary: just click a button and you’re on Mars. You can choose from a variety of global maps including topography, Viking images, Day and nighttime infrared, and visible color. It also has footprints for high resolution cameras like HiRISE, CTX, MOC, CRISM, and HRSC, with links to the full-resolution images. And most exciting, it has 3D topography! Now you can fly around in Valles Marineris or check out the view from Olympus mons.

The view from the edge of the Olympus Mons caldera in Google Mars.

The view from the edge of the Olympus Mons caldera in Google Mars.

Olympus Mons dominates the horizon in this Google Mars view.

Olympus Mons dominates the horizon in this Google Mars view.

Another way-cool feature is the ability to zoom into panoramas taken by rovers and landers, as shown here for Opportunity.

The Opportunity rover's traverse. Each camera icon is a panorama that you can zoom into.

The Opportunity rover's traverse. Each camera icon is a panorama that you can zoom into.

Part of the Rub al-Khali panorama taken by the opportunity rover.

Part of the Rub al-Khali panorama taken by the opportunity rover.

And finally, you can load selected Context Camera images right onto the globe, to take a high-res look at areas of interest, such as the Olympia Fossae troughs shown here. I don’t know what’ you’re waiting for: go download the program and try this out for yourself!

CTX image of the Olympia Fossae troughs.

CTX image of the Olympia Fossae troughs.

Potential MSL Site: Holden Crater

September 17, 2008

The next landing site that we heard about was Holden Crater. Holden is a 154 km diameter crater formed early in martian history that happened to fall smack in the path of an extensive fluvial system. There was a long chain of craters connected by water-carved channels  and then the Holden impact occurred and interrupted that flow. It looks like Uzboi vallis, one of the channels, then breached the rim of Holden crater and began to fill it with water, but there is no exit breach, so the Holdin basin apparently became the end of the line for water. When Uzboi vallis broke through the crater wall it caused a pretty violent flooding of the crater and carved into light-toned layered deposits that may have been laid down by an existing lake.

The landing ellipse is on a “bajada” which is a fancy term meaning lots of alluvial fans. (an alluvial fan is a fan-shaped deposit that forms downhill of a rocky location eroded by water) The bajada is nice and flat, but still contains some interesting inverted channels, and studying the fans could tell you about how much water was available to form them. In other words, the fans could tell you about the early climate on Mars!

There are light-toned layered rocks at the edge of the fans and near the Uzboi vallis wall breach that look like they were probably deposited by a lake. These rocks have very thin layers that can be traced for many kilometeres in HiRISE images. The lower units of these deposits also have a clay signature, which is good for the preservation of life. An interesting point was that the clays apear in both the crater rim and the layered deposits in the crater, so we may have an identified source and sink.

In the discussion of this site, someone brought up the fact that the clay signatures at this site are not as strong as those for Nili Fossae or Mawrth Vallis. But the response to that was that there is not a one to one correlation between spectral signature and abundance. Lots of other complicating factors such as grain size, mixtures, and optical properties of the crystals are involved.

It was pointed out that the lack of phyllosilicate diversity could mean that ther were fewer chemical gradients for life to take advantage of. But then the counterpoint was raised that the atmosphere-water contact would be a great chemical gradient, and if there are only chemotrphs (no photosynthesis) they would likely take advantage of that.

To me, Holden seems like a fine site, but I got the impression that i just doesn’t have people excited. This may be because it doesn’t have a large group following like some other sites do. On the other hand, it has some diverse morphologies and interesting mineralogy, and could teach us a lot about the arly climate on Mars. Still, my prediction is that it won’t survive this week because for whatever reason it does not have people as excited as other sites.

Potential MSL Site: South Meridiani

September 16, 2008

The south Meridiani landing site is a newcomer to the bunch. It was added earlier this summer as a replacement for the north meridiani site. The south Meridiani site is about 100 km due south of the Opportunity rover landing site and about 100 km due east of the Miyamoto site. What makes the south Meridiani site interesting is that, just south of the landing ellipse, you transition from Meridiani plains material to ancient, water-eroded hills containing phyllosilicates.

The site has good context, in that we would land on the same sort of material that Opportunity is studying. However, the context for the phyllosilicates in the hills is bsically zero. We don’t know where they came from or how they got there.

For diversity of mineralogy, the rocks in the ellipse are probably sulfate-bearing just like the ones Opportunity sees, and are also rich in hematite (probably more blueberries). South of the ellipse, the clays in the hills are pretty diverse, with different chemistries.

Habitability? Well, we are pretty sure the meridiani rocks were once soaked in groundwater, but that water may have been a very salty and acidic brine. We don’t really know about how the phyllosilicates got there, but if they were marine or lake sediments, that would be great for habitability. However, they could also be crater ejects, which is somewhat less good.

As far as preservation goes, both sulfates and phyllosilicates are good at preserving organics under some conditions, so you would have two different, but good chances to see preserved biomarkers.

The mission at south Meridiani would be three phases. Phase 1 would be landing on the meridiani plains and using the new tools on MSL to better understand the same general rocks that Opportunity has been studying. MSL would land in a place that is in lower layers than Opportunity, so would fill in some of the earlier story. Phase two would be driving south to the contact between the meridiani plains unit and the ancient clay-bearing hills. And phase three would be exploring the hills.

The discussion phase once again brough up some tough and important questions about the site. Someone asked whether, when we cross the boundary between the plains and the hills, we are seeing the transition between a sulfate-forming environment and a clay-forming environment, or are we just seeing “before and after” and missing that transition. Someone pointed out that even if there are “missing layers” due to some period of erosion or non-deposition, that still contains information, because the surface would be weathered and altered before the new rocks were laid on top.

Someone else pointed out that this is a perfect example of an interesting mineralogy site, but with no context. We don’t know the whole “source to sink: story of the phyllosilicates. It was compared with all of the interesting rocks that Spirit has seen in the Columbia Hills: all very cool, but hard to piece together into a story.

Another very important question was whether the clay-bearing rocks had any distinctive appearance. Because MSL will probably not be able to identify them from very far away. (at best, ChemCam, the laser, might be able to… that’s part of my future research, so we’ll see) There wasn’t a good answer to this, though the phyllosilicates are seen in somewhat diagnositc “fractured” rocks.

The bottom line is that this site would be interesting because we would learn more about Meridiani, and would be able to cross a transition and explore very old clay-bearing rocks. However, the context for those clays is pretty weak, and we might end up being totally confused due to that lack of context. This site does have the advantage that it is incredibly safe. Meridiani planum is FLAT. I don’t think it’s the best science site, but it is an acceptable science site, and it may end up surviving or being brought back later on because it is so easy to land on.

New insights into ancient water on Mars

July 17, 2008

The evidence for a warmer, wetter ancient Mars just keeps piling up! In 2 new papers, the team for the CRISM spectrometer onboard NASA’s Mars Reconnaissance Orbiter has reported new evidence for water on the surface of ancient Mars, based on the ubiquitous presence of water-bearing minerals.

Universe Today has a great post up on the findings, so I won’t repeat too much of Nancy’s explanation.

In brief, the CRISM team has identified a whole new suite of minerals on Mars, in addition to a few already observed, that only form with copious amounts of water. While some of these minerals are associated with local deposits that look like sedimentary layers set down by surface water, others seem to be present across vast regions of the ancient southern highlands. In particular, the minerals tend to be associated with the ejecta, floors, and central peaks of craters in the ancient terrains. Because the impacts probably dug up the minerals from several kilometers down in the crust, the crust must have been altered by water to at least that depth. For example, the image below shows where CRISM has detected phyllosilicates (a hydrated clay mineral) in one region of the highlands. Because almost every crater has a phyllosilicate detection, the basement material has probably interacted with water throughout this region.

Mustard et al. (2008), Figure 4a

We tend to think of “Mars” as one place with a history that can be described by one storyline, even though Mars is a whole planet with as much surface area as dry land on Earth. What’s really great about these findings is that they really bring home that the surface of Mars probably had just as many different environments as Earth does now. Mars scientists have used the composition of minerals and their geologic context to identify ancient hydrothermal springs, shallow seas, lakes, and floods on Mars. With all of these different environments, life very well may have been able to eke out an existence in one of them…