I asked this question in another thread but didn't get an answer,this is certainly the one to ask it in,maybe it has been discussed already but I haven't run across it. Could someone speculate on how this white line compares as far as depth with what the lowest point the rover was able to drive to and analyzed in endurance crater ?

We don't know exactly where we are in the section. We may be either above or below the units we looked at in Endurance.

--Bill

Hopefully once Opportunity enters Victoria and gathers compositional data on the various layers it will be possible to match them with comprable layers in Endurance. In the meantime I wonder if the massive blocky layer most prominent in Cabo Frio is a match for a similar layer in Burns Cliff?
Click to view attachment

Attached is a copy of the stratigraphy observed at Burn's cliff, from the Grotzinger paper. Are we looking at the sand sheet or the dune field?

--Bill

I am usually willing to go out on a limb with some speculation, but even I am hesitant to make that correlation. You could very well be correct, centsworth_II, but I remain stratigraphically lost atm. I'd guess that we are not too straigrraphically distant from the layers at Endurance, but hey.

Sometimes stratigraphy expresses itself in the shape of similar landforms across wide areas, but we really need to see more here before coming to conclusions. As far as the science we can perform on these rocks, we just arrived here. By the time Opportunity arrives on the other side of the sun, we'll probably have more information.

What I'd be looking for is something like the Whatanga contact, which is distinctive chemically and physically and/or the Wellington contact, which is physically distinctive. As I've seen in the Pennsylviania Pottsville, you can have a massive blocky unit anywhere, anytime. We'll look at the section here and see what matches with what.

We had distinctive units at the Payson exposure but I'm not sure we spent enough time looking there. And I wish we had done some IDD work there and had also been able to visit the "Payson Promontory" site, which appears to be equivalent to a Cape at Erebus.

We've got a good start, but only a start.

I don't have the time, patience, or intellectual fortitude to get as deeply into it as a lot of you all! But like everyone else, I'm looking forward to a layer-by-layer correlation between Endurance and Victoria.

Concerning a move up or down in the stratigraphy of Meridiani during the trek to Victoria:

As I recall, there were definite changes in the chemistry between layers in Endurance. It seems if Opportinity was seeing lower layers during its trek this would show up as similar changes during the occasional inspection, the most recent of which is taking place right now on the rim of Victoria. I haven't heard that any such change in surface chemistry has been seen.

If Opportunity moved up in the stratigraphy during its trek, I would also expect chemistry changes, but there is no way to know if that is the case. Only identifying a layer that definitely correlates between Endurance and Victoria will tell.

Anyway, those are my feeble thoughts. Obvious, I know.

centsworth_II: A correlation to the beds in Endurance would be a Holy Grail, as Bill is fond to say. We all need to keep looking for that connection. Your observation of a weathering/erosional pattern is a legitimate way to do that. It just isn't conclusive yet, with the imagery available.

Bill: This is really speculative on my part, but I might see some displaced blocks in the recent subframe from the upper rubble under the Beacon that resemble the Whatanga contact. I was thinking that the coarse texture in the rock on the left side of that image might indicate a higher energy depositional environment, but it very well might be evidence of a secondary process, as at Whatanga.

Among other things that fascinate me tonight, I find myself looking at the more or less "in place" bedrock below Cape Verde where tdemko illustrated contacts between the ejecta, the foreset laminae of migrating dunes, and what he called the toesets of migrating dunes. The steeper foreset dune faces have me thinking also of the Wellington contact. From the limited close-up views of critical rocks we've seen so far, I'd have to be nuts to speculate as far as I have. This rover needs to get past the conjunction and back on the road. There is much to see.

This has become pretty much a "you snooze, you loose" kind of forum. I hate to go to sleep at night, because when I wake up in the morning, this corner of Mars is likely to have become a whole new place. UMSF pretty much keeps us on our toes. Not only do we not want to miss the discussions where we get insights from other members, but we had better have done our homework before coming here.

Yes, those sub-frame Pancams were a real treat. And a tease, just before the conjunction hiatus. Almost as bad as 'who shot JR?'. And frustrating: we're walking the outcrop and we start seeing this wonderful float that we have no idea where it came from. And then we wake up...

But this (and hopefully other Pancams) will give us food for thought during the upcoming break.

With the international makeup of the forum and the timing of the image posting on Exploratorium I find myself getting up in the wee hours (in the USA) to read and post on UMSF. I'm not neurotic or addicted, this is simply a practical time to post for our overseas comrades. Or so I rationalize...

--Bill

Hi

Here here the Beacon Rocks in a closer view. I succeed to realize stéreo color pic of it.

The only left view of the pancam through all the filters.
Click to view attachment

A parrallel eyes pictures, resized to can match the two frames :
Click to view attachment

And an anaglyph, at 200% of the the original size :
Click to view attachment

Here is an L256 Pancam of Capes G1 G2 and H1. I was hoping to get one or two other channels to the several Pancams we've gotten so we'd have something to work with during the conjunction break, but not joy.

I'm thinking that one of the first tasks after conjunction will be a hi-res pan from The Beacon...

--Bill

One of the things I have been looking for since we've gotten good views of parts of the crater's circumference, is a place where the deepest stratigraphic layers are exposed. That is the ultimate goal, is it not? I am not concerned at the moment whether the deepest layers are accessible to the rover. Where are the deepest apparent layers? From our current position, the deepest rocks I can see are those of the soup dragon. I realized that was the same area where the lineament was observed on the far side. Could that lineament mark a concentric fault where rim rocks of the initial, transient crater collaped/slumped inward to create the final, shallower crater?

WindT and ngunn were also talking about slumped features in the soup dragon thread, though they seemed to be talking about the outcrop above and left of the dragon in this same area.

I had been looking for some long baseline imagery of this area for a while, and I finally found some. I think I had to mix an R1 with an R2 to make this pair for an anaglyph, but it works reasonably well. I added a view from MRO that is somewhat distorted to approximate the X scale in the anaglyph.

This would be a good area to get a better look at as a potential future target. Are those deeper rocks really stratigraphically deeper? Is the lineament buried in some places by later layers?
Click to view attachment

Cosmic,
I tried to see if there was any obvious fracturing which might be revealed by the faces of the cliffs around the crater. I fit, by eye, straight lines to the flat faces of some of the cliffs. My assumption was that the flat faces of the cliffs might represent planes of weakness formed by fracturing of the bedrock. The procedure was very subjective. A different person might have drawn the lines in a different orientation. And a slight difference in placement could make a significant difference in their interpretation. For what it's worth, here's what I did. I wouldn't want to use this to make any profound conclusions about the crater. Curiously, the lineament that you pointed out may be in line with some of the cliff faces along the northern rim.

Click to view attachment

You may be on to something, Gray. In the Alabama Pottsville Formation on the Warrior Plateau, joints tend to align in two preferred directions. Although the Pottsville is undeformed, this joint orientation does relate relate to the Appalachian deformation to the southeast. Last year we looked at a MOC image of the area around Eagle crater and Endurance crater and marked the directions of the many "anatolia lineaments" in that locale. There is a trend and it does seem to be related to the trend you found at Victoria. Image attached.

Having said that, I think that the layers pointed out at the "SD" by Tom are not that unusual. I do think that the "SD" is a larger piece of the cliff-forming unit that has broken off at one of these lineation and is slumping downhill.

As shown on the attached MRO image, there is a persistent blocky unit that has a distinctive weathering appearance. This layer can be traced in the northeastern and eastern capes, as pointed out on the image. This unit is essentially flat-lying and the ground surface slopes to the southeast, so the blocky unit is at the bottom of the cliffs on the northeast rim and gradually reaches the top of the cliffs or the outer rim at the east. Therefore, the southern half of Victoria should expose stratigraphically lower strata.

A similar blocky unit can be traced from Duck Bay ccw on to the west.

--Bill

Wow, you've looked at the images of the crater a lot more closely than I have. I see what you mean about the distinctive blocky layer being closer to the surface in the south than the north. Good call. If Oppy can't make it safely into the crater, maybe she can do just as well by circumnavigating to the south.

Have you been able to correlate the blocky weathering horizon it to any of the images of the clliffs at Cape Verde or Cabo Frio?

Bill, I'm a bit confused about your blocky unit - at the north end of your image it appears to be much deeper than the "thin white" layer, but towards the south end it appears to approach the white layer.

Could it be that the thin white layer is genuine stratigraphy, while your blocky unit occurs wherever local slopes are greatest? Of course the question is why are the slopes greatest there?

Also, if you look at James's pancam/MRO comparison, the blocky unit doesn't seem to my eye to be a coherent layer.

I'm going to call it a "blocky weathered yadda" instead.

It may or may not be there; looking at the MRO image, it looks significant. In the Pancams, particularly James' MRO/pancam comparison, perhaps less so. I noticed the white unit/blocky unit convergence, but decided not to add that complication to my observation. Good call, Fred.

I'm inclined to want to correlate that blocky unit with the block unit at P4, Cabo Frio.

We'll be able to see more with additional imagery after Conjunction.

Victoria is a puzzle-box. Open one box and up pops another.

--Bill

something about those 'beacon rocks'...
for example: from sol 967

it especially noticeable on the lower middle rock, those crisscross striations, im assuming one is the actual bedding, but what is the other?

they do seem to follow gravity downwards... so:
- are they just erosion channels created by stuff above them falling down?
- wind blown channels upwards?
- or might they be renmant scratches left by snowpack slumpage?

ii dont remember seeing anything quite like this before... any thoughts?

That's an interesting pile of specimens, isn't it, atomoid. If I had to guess, I'd suspect the diagonal striations are the sedimentary laminations. But those vertical lines are curious. At first I thought they were simply trails left by fine sediment falling over the surface from above, but the hole left by the chunk broken from the left side of that block seems to show that the nearly vertical planes penetrate the rock, or so it seems. I'm almost tempted to suggest something, but I am going to bite my tongue until we see more, as I suspect I am wrong.

It really seems that the influence of fracturing on this crater's current appearance is strong. I see many of those that Gray and Bill pointed out, and I could draw a picture with a set of my favorites, too. I am having a difficult time distinguishing between those that I think might have been significant in the early. formative stages of this crater from those possibly formed later, and that might also have had an influence in Victoria's later stages of modification.

I think we will learn a lot as Opportunity gains mobility in coming sols, but I am disappointed that we haven't yet discerned more of the structure and stratigraphy of this crater so far. Let's keep an eye out for new papers and new data. The experts are surely already working on exciting publications.

This rubble pile is complex but interesting. At first glance, the criss-cross patters are finely-bedded sandstone with wind-eroded cross striations. There may be more to it than that, but woithout a closer look, the simplest explanation fits for the time being.

I'm looking forward to more MRO imagery of the Meridiani plain, this should give a great deal of insight on the natur of the anatolia lineations.

--Bill

While things are quiet can you stratigraphers clear up some possible confusion on my part? I thought I understood from Bill's earlier posts, e.g. in the Big Crater thread, that a southward overland trek would take us gradually downward through the stratigraphic sequence. Now we seem to be saying identifiable beds are buried deeper under V's south rim than the north rim. Is that not the opposite (and much steeper than) the previously suggested regional dip? How does all this fit with the topography of the area, the fact that V is on a gentle slope and the unique elevation of the Beacon??? I know this is something of an experts' thread but an overview for beginners would be most welcome at this stage: not theories about origins etc. but just what we are actually seeing so far in descriptive terms - maybe a sketch?

ngunn,
That's a very appropriate request. What would be very helpful would be a summary of the geology that we've seen between Endurance and Victoria. To be honest, I don't think I know enough about the geology and topography of the area to provide a very complete summary.

ngunn: I'll take a stab at responding to your very good question. Surely others will comment. It seems to me that the details of what is going on here with regard to the structure and stratigraphy are still very much up in the air. But if we step back and look at the regional picture, some things are known. Peer reviewed publications have noted that the layers of rock Opportunity has observed since sol 1 are very horizontal on a large scale. I don't remember the official number, but if there is a regional dip, it is very small. I think less than 1 or 2 degrees, as I recall.

Over the course of the traverse members of the MER team have frequently noted that driving south would result in Opportunity going up the stratigraphic section of rocks. That seems to be the result of the fact that most of the distance between Eagle crater and Victoria was up hill, to higher elevations. As you climb a pile of horizontal layers, you obviously will encounter higher layers in the stratigraphic succession. This appears to be what has happened between Eagle/Endurance and the Hell of a View location. After HOAV we went down in elevation, and I think a bit up and down before getting to the annulus of Victoria, where I think we travelled mostly upward to the current location. In the past I have argued that some observations indicated that there was also a regional dip toward the south, which would have resulted in the observation of higher stratigraphic layers in that direction even if elevation was not increasing, but I now think those observations only noticed local variations from the average flatness.

For me at least, that leaves us with a bit of uncertainty regarding where in the pile of layers we now are. Add to that the probability that local events at Victoria have added some new layers and maybe removed some others, and you can see the difficulty in correlating any of the rocks we see here to those seen earlier in the mission. More detailed observations of the various layers at Victoria will eventually help us make more sense of the picture at our feet, but I really think it is too early to say much more with the information we have at this point. We need more than detailed pictures. The miniTES, Moessbauer, and APXS spectrometers will do a lot to fill in some of the gaps.

We don't have a good correlation between layers seen here and previously seen layers, though some of the individual rocks look very similar to those seen previously. My guess is that we are stratigraphically close to the where Opportunity has always been, and that the best option we have for discovery is to take a look at any rocks at higher elevations (luckily nearby), and then find the best route to good exposures of deeper rock. Finding deeper rocks has always been the main goal for this rover.

Thanks for that CR. So, significantly off-horizontal layering inside Victoria (other than slumping features) will be a surprise if confirmed?

Also, recall that the rock horizons, once they are laid down, are then at the mercy of tectonic and isostatic movements of the crust in the region. For example, let's suppose that Meridiani was once the site of a moderate-sized sea. Remove a vast majority of the water by evaporation (and assume that the water has now moved, via atmospheric transport, to the poles), and a rather great weight has been taken off of the rock beds at Meridiani and placed, instead, at the poles. The crust at the poles will tend to sink under the weight of the added ice, while the crust at Meridiani will tend to rise a bit with the release of the water's weight.

Or, assume that the large patera formation in Meridiani Terra was built after the Meridiani Planum rock beds were laid down, and the pressure of the magma underneath the Terra region pushed the entire region (including the Planum region) upwards, and then dropped it down as it escaped and was piled onto the surface.

In either of these cases, the rock bed horizons may simply follow the surface levels, shifting as the underlying crust shifts (rather as a rug will conform to the surface of the floor, even if the floor shifts underneath it). Moving up and down in elevation will make no difference as to where in the strata the surface is located at any given place.

For movement along surface elevations to move you up and down through the rock strata, you have to have some deflation or erosional process occurring that has caused the elevation changes. Literally, you have to have a process that removes some of the layers to allow you to descend within the strata.

I'm not saying that moving downward in elevation wouldn't take you deeper into the strata. I'm just saying that you need to prove that the elevation change is a result of upper layers being stripped away before you can make that assumption.

-the other Doug

dvandorn, cosmic,
Those are excellent summaries of the local geology and very good reviews of some of the major factors which influence sedimentary strata. If you're not a teachers, you should be.

Perhaps, but there are other complications. I think the creation of Victoria is likely to have locally deformed some of the bedding in ways other than slumping, and the later burial of the crater might also have resulted in layers that are not horizontal, if any of the burial layers are still preserved after the exhumation. There are other less likely possibilities, but all kinds of amazing things will be observed that can't be seen from here, when Opporunity starts circumnavigating. Just wait and see. Have we ever been at a loss for wonder as these two vehicles have done what they were so magnificently designed to do...rove across an alien planet and phone home?

I only pray that this brave rover can survive another year on this alien planet. The ground truth the rovers have given us has proven beyond any doubt that some of the things we see from orbit are difficult to interpret without eyes on the ground that can see the more vertical surfaces in some detail. The MER missions, and their synergy with the orbiter data will be recorded in history as one of the most significant achievements of our species thus far.

Just wondering if this "white layer" is the at the same level in both craters..? A common boundary between layers?

Click to view attachment

That's a damned good question, Stu. I don't know about anyone else, but I am not ready to suggest it is the same layer. It seems possible, but unlikely to me. As I've repeatedly said, I don't think we've seen enough of the layers here in enough detail to make correlations like that. At least, I am not ready to.

Your comparison of rim-side views of both craters did inspire me to create one of my own, and one which has become one of my favorite side-by-side comparisons of Opportunity's recollection of the two rims.

I didn't attempt to scale them identically. I simply matched the features to be similar in size. The Endurance view was created in MMB with slinted's calibrated color pancams. The Victoria view is a crop from a panorama made by James. If I were to give a name to this picture, I'd be tempted to call it "deja vu, all over again," though maybe not exactly. How's that for hedging?
Click to view attachment

Good choice of pictures, Cosmicrocker

There does seem to be interesting comparisons
A large blocky unit overlain by well brecciated layer
The “white layer” beyond both capes seems similar
Both have nicely plained off rocks on the inner slopes.
Finer layers are more evident in the slopes of Endurance.

A difference or two are, there are more exposed rocks outside of the crater at E
And sapping of dust around the rim of E, leaving small holes seems much more common.

I agree it is too soon to make accurate comparisons

Roy F

Here's an interesting idea, about landforms (gullies in particular) possibly being formed by melting of magnesium sulphate crystals (epson salts) that have formed in below-zero temperatures. Any of the experts care to comment on how far-fetched that idea is?

"This looks like that" arguments are always a bit problematic. As far as I can tell, we are dealing with an experiment on a lump of the stuff maybe 1 m across, which produced 'landforms' similar in appearance to features on Mars that are 1000 times larger. It's not the greatest argument that the features on Mars are made of the same stuff. Quite apart from the fact that multiple materials might produce similar effects - really you need to do this with a variety of salts, and other materials, and see what they all look like. It's an interesting idea, but it's not strong evidence for anything yet.

Phil

This must be the same source as in Alex's 'Mineral discovery' thread. Sounds very interesting to me. Much has been written over the years about the role of subsurface ice on Mars, but not (at least in popular sources) about the behaviour of frozen concentrated aqueous solutions which is probably closer to what's really there than plain water ice as such.

One point I wanted to make, which I don't think is mentioned in this thread:

After Endurance and Victoria were created they were filled in with aeolian material which was subsequently diagenetically altered as the groundwater table rose and fell, with water seeping into the crater. In Edgett's paper, he describes the sediments within the interior of exhumed craters as having different physical -- and presumably chemical -- characteristics than that of the exterior/country rocks. If we extend this to Victoria and Endurance, this would seem to imply that the stratigraphic sequence we're seeing within each crater may not correspond to the stratigraphy outside of the craters. And, if I'm reading it right, because Victoria and Endurance were created at different times, the geochemical environment under which the crater-fill sediments were altered may have been different for each crater, and so the stratigraphic sequence seen in one crater may be completely different that observed in the other crater.

I only quickly skimmed Edgett's paper, but does my interpretation make sense??

Oh yeah, and the white horizon near the top of Victoria may represent the upper level of the water table, as the Whatanga Contact seems to represent at Endurance. But the kink seems to be that they were not formed during the same timeframe.

I don't see the slightest evidence for Endurance and Victoria being infilled and then exhumed. They are quite different from the filled and exhumed craters that Ken described in his paper as well. To me they are simply variably eroded craters formed long after the depositional sustem at Meridiani shut down. The only infill they have are the unconsolidated dunes on their floors. So sign of indurated indurated internal material at all.

Jon

I'll second that. I don't see what the extra complication of infill and excavation adds to the explanation of these craters. I think the apron is hard to explain under that scenario - wouldn't it have been eroded away also during the excavation process?

Exactly what I've been thinking. The annulus around Victoria is obviously quite altered; it is quite dissimilar to the etched terrain that surrounds it on all sides. And it is arrayed around the crater exactly as an ejecta blanket would be arrayed.

I'm afraid I really don't buy the buried/exhumed theory for Victoria, either.

-the other Doug

It seems to me that there is a tremendous amount of regional evidence for the burial and later exhumation/partial exhumation of old craters in Meridiani, and that is evidence enough for us to consider the possibility that it may have occurred at Victoria and Endurance. It seems to be very common on Mars in general, not only in the Meridiani region. I do agree that it is a challenge to see the evidence here. Indeed, it may not have happened here. I still think we haven't seen enough of the local detail to draw any solid conclusions yet, and I am still looking for definitive evidence. But so far I think I am seeing clear evidence of a rather complex stratigraphy, undermining and collapse of more competent layers in the formation of the cape and bay morphology, and the planing down of most of the impact ejecta.

aldo12xu: I don't know that we can be certain the filling sediments were aeolian, though that would be a logical guess. Edgett actually mentions the posibility that the fill could have resulted during a later, very different regime.
I think that is somewhat speculative, and one reason why I think we need to see more detail. There are a lot of potential variations on the theme, if burial and exhumation is the story here. At the moment, I can imagine the possibility that Victoria was significantly eroded prior to its theoretical burial, and that the current state at which we see it is one where it is largely exhumed. There may be little evidence remaining of the fill. But that is only a working hypothesis, and not a conclusion. For the time being, I am keeping the sunglasses on.

<sigh>, I tend to run hot-and-cold on the crater exhumation issue. I can see how sand can blow into the crater and bury it, but I'm still having problems with sand blowing out of the crater. My opinion on this will remain floating until it can be nailed down...

--Bill

It's not so much as the sand getting blown out of the crater as the whole landscape being lowered. If the crater infill is more indurated than the surrounding material the infill can end up higher than the surrounds.

Jon

OK, I was thinking along the lines of the infilling material being removed from the crater. I may have a misunderstanding of exhumation (eh, I get tunnel-vision from time to time). I'll hit the Web and read up.

There are several exhumed craters visible under the ejecta blanket in my Post# 89 in this thread.

--Bill

Hey, Jon, welcome on board! I'm sure forum members will find your insights to be most valuable.

It was Edgett's Figure 21 that stuck out in my head where Endurance and Victoria are included in an example of a possible exhumation sequence. I, too, am on again/off again with regard to the exhumation theory. It seems like a good regional theory with lots of good examples of former crater infilling (Figures 13, 14, 15). But, as far as where Endurance and Victoria fit in, I agree with Tom that we might not have enough data to draw any definitive conclusions.

40 Mb: http://marsjournal.org/contents/2005/0002/...s_2005_0002.pdf

I would think the exhumation theory is quite a bit less probable than a standard erosion model. There should be plenty of observational evidence around the rim to help determine the truth though. The exhumation model would have to account for the fact that the upper layers of the rim would have been exposed to the wind and dust for eons longer than the lower ones. This would result in a well rounded and fairly low-profile rim.

The other question is where did the fill come from? If it was regional dust then what was different about the wind which filled the crater compared to the wind which exhumed it. The same wind couldn't do both right?

And at Victoria the edge of the crater is being eroded back as evidenced by the capes and bays and we don't know what the original diamter of Victoria was. This recession would eliminate the raised and upturned rim of the crater, along with the planing of the plain...

We can speculate, but truth is, we don't really know.

--Bill

Dust in a crater "lives" in a different microclimate than the dust on the plains. Perhaps being in a crater lets the dust collect a fraction more water, cementing it a little bit better to its neighbors than the dust out on the plains. This would cause differences around the rim of the crater, as different rim locations keep different amounts of moisture, and differences between craters of various sizes, creating minimum/maximum sizes for exhumed craters, and differences based on latitude, possibly limiting where these are found. Is this what we see?

I see what you are saying, hendric, and I can imagine that possibility. The problem for me is that there are so many possibilities to consider in this alien landscape that I don't know which variables are the most important here. Your idea is a concept I had not considered, but it seems testable. Two of the largest bays are on the NW side, but that also seems to be the steepest side, so what is the controlling factor?

There have been a lot of interesting observations noted by people in this thread, but so far we haven't managed to pull them together. I've been trying to take advantage of the slowdown caused by the eclipse by looking back at the Opportunity imagery we have, and comparing it to the amazing MRO image. I really had hoped to have at least made some progress, but I will admit that this crater still bewilders me. The heck with festoons...a case of Mars bars goes to the first to identify remnants of the proposed crater fill.

That's it exactly, Tom. This is an alien landscape and the processes at work here are a wee bit different than the ones on our warm, wet, oxygenated, tectonic landscape. We see a lot of little clues, but not the big ones that will tie things together and result in the big AhHA.

--Bill

The similarities I suggest greatly outweigh the differences. We see suprisingly familar products of the interaction of wind, water, rock and volcanism. Plus the basic principles of field planetology are still the same. However, even on Earth, one would still walk round a place like this for a while aborbing clues muttering to oneself before jumping to conclusions - I mean formulating hypotheses.

Jon

Sure, there are the processes of weathering, erosion, transportation, deposition and lithification, but the details of those processes are at least, and probably more than, a wee bit different on Earth and Mars. The "warm, wet, oxygenated, tectonic terrestrial landscape" is the significant difference, whereas Mars has a thin, cold, non-oxidizing atmosphere with little of no liquid water. Although this has not been studied, I'm sure that there is a timeframe difference. On Earth a given landform might take 1,000 or 10,000 years to form and mature, on Mars a given landform might take 10 million or 100 million years to form and mature. I have the impression that processes on Mars are incredibly slow by the human time reference.

--Bill

Certainly the rate of landscape evolution is probably the biggest difference. But there is huge overlap. Martian landforms probably (based on the extremely blunt instrument of crater counting) probably range in age from zero to billions of years. Terrestrial landforms range in age from zero to perhaps a billion years. But the products of these processes are still remarkably similar for all that.

Lots of areas on Earth also dry and cold, and while the surface of Mars is not oxygenated, it is certainly oxidising. What this subtle difference means in terms of mineralogy and chemistry has yet to be determined.

The differences then are in degree, not in kind.

Jon