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Fraser
2004-Feb-11, 05:53 PM
SUMMARY: Now in orbit for more than a month, the European Space Agency's Mars Express spacecraft has been delivering mountains of data back to Earth. An image taken on January 21, 2004 is of the caldera of Olympus Mons, the largest known mountain in the Solar System. Olympus Mons is 22 km high and the caldera has a depth of 3 km.

What do you think about this story? Post your comments below.

Chook
2004-Feb-11, 07:45 PM
I don't want to get into "The Electric Universe" thing - but what causes these surface features of Mars - shifting plates, cooling and shrinking of the surface crust, close collision with another body, (God help us) electricity from another body? What? :)

Duane
2004-Feb-11, 08:06 PM
Most features seen on Mars are impact related (http://www.impact-structures.com/). The large volcanos and the Valles (valleys)are likely a combination of shield volcanism (http://vulcan.wr.usgs.gov/Glossary/ShieldVolcano/description_shield_volcano.html) combined with some crust deformation caused by a combination of planetary cooling and the weight of the shield volcanos.

Some of the features display evidence of possible water erosion.

Nick4
2004-Feb-11, 09:13 PM
I will use this as my wallpaper mars has always bean one of my favoret sky objects thou i have never seen this valcano so much in detail.

VanderL
2004-Feb-11, 09:50 PM
Most features seen on Mars are impact related. The large volcanos and the Valles (valleys)are likely a combination of shield volcanism combined with some crust deformation cause by a combination of planetary cooling and the weight of the shield volcanos.

What shield volcanoes can create something like Valles Marineris (which shield volcanoes exactly), planetary cooling shouldn't be visible in only one place and water erosion is also very unlikely (a 9 km deep valley?? and where did all the material go, there is no outflow), I saw some very strange features in the Valles, a furrow cut into one of the big mesas that is very shallow on the top of the mesa and very deep at the edge, and everything so sharp that it looks like it is cou out with hatchet.
I hope we get a lot more details, but my guess is that Valles Marineris wasn't created in any ordinary manner.
Cheers.

Duane
2004-Feb-11, 10:20 PM
Sorry VanderL, I disagree. The explanation of crustal cooling and the resultant deformation of the lithosphere (http://www.cotf.edu/ete/modules/msese/earthsysflr/lithosphere.html) easily explains the Valles Marineris--similar processes are seen on Earth.

When you look at the position of Valles as compared to the main shield volcanoes (olympus and the Tharsis Montes (http://volcano.und.nodak.edu/vwdocs/planet_volcano/mars/Shields/tharsis.html)) there seems to be a striking correlation. Considering the incredible weight of the outflows at this location, it almost seems inevitable that some degree of crack and stretch would occur.

That seems to be the most likely explanation for the Valles.

Furthermore, with this senerio, you would not see outflow, and depth would be simply a matter of how far the crust was forced to stretch before reaching equalibrium.

Finally, Valles Marineris is not the only example on Mars of rift valley (http://www.cotf.edu/ete/modules/rift/rvwhatisriftvalley.html) like structure, it is just the most well known.

VanderL
2004-Feb-11, 10:40 PM
Ok Duane, let me try to explain what I mean.
http://www.spaceref.com/news/viewsr.html?pid=11827
Here is the image I'm talking about, in the upper part you can see 2 big mesas. The upper one, if rifting is assumed, looks like the surroundings rifted away in all directions. The second mesa has the furrow feature I descrided earlier. How can this be caused by rifting, and when rifting is the mechanism, the material (that previously connected to the mesa) still has to go somewhere, just look at how sharply defined the cliffs are, some rubble must be visible, the canyons floors are wide, flat, and quite empty.
Cheers.

Duane
2004-Feb-12, 12:14 AM
yes that is an excellent examle of a earth-like rift valley (http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS007&roll=E&frame=14338&QueryResultsFile=10765435593812.tsv) structure. The photo I have attached here is a shot of one on Earth, from space.

Look familiar? The same type of structure can be seen in the earth photo as the photo you have linked from Mars--the sharp cuts, the material (or lack thereof) left behind, etc.

There is no loss of material, VanderL, the ground has split. That very high-resolution photo makes it hard to see that split, but if you go to older photos of the Marineris, you can see the "rip" in the crust--good enough that you can almost sew it back togeather.

The tectonic plates (http://www.seismo.unr.edu/ftp/pub/louie/class/100/plate-tectonics.html) of earth also show that same "ripped" type look, although the processes causing them are somewhat different. Look at the Atlantic plate between South America and Africa, for example.

Higher-resolution space photos of the Great Rift Valley of Earth also show the same sharply-defined cliffs with wide, flat, barren canyon floors.

Chook
2004-Feb-12, 12:49 AM
Sorry fellows - but until Damienpaul created his course, us less informed amateurs need a little assistance with the nomenctature.

"Impact-related" - assume it relates to hits from asteroids;
"shield volcanism" - ?
"mesa" - it that the surface feature that looks like a flat-bottomed lake with steep sides but no water?
"lithosphere" - ?
"valles" - valleys?
"rift-valles" - ?
"rifting" - ?

Sorry about this but if we are to try to intelligently follow the conversation of you experts then we have to know what the words mean.

Many thanks :)

Duane
2004-Feb-12, 01:07 AM
Chook, I have added links in my posts to most of the words on your list.

VanderL
2004-Feb-12, 10:35 AM
Thanks for the links Duane, but they don't help me understand what i think I see on Mars. Of course on Earth every feature undergoes significant erosion, while on Mars only wind (sand) erosion is working. Questions
1. Rifting on Mars is not due to plate tectonics?
2. An isolated mesa in Valles Marineris with extremly steep cliffs on all sides can be formed by rifting?
3. Circular cliffs can be formed by rifting?
4. Is rifting is an ongoing process on Mars or is it an ancient process (planetary cooling?) that has stopped long ago, because erosion must be stronger I think.
I'll think of more questions later, again thanks Duane.
Cheers.

johnm
2004-Feb-12, 12:47 PM
How about the effects of the huge temperature swings on Mars? Over millions of years this could also generate some erosion.

damienpaul
2004-Feb-12, 12:52 PM
perhaps the circular shaped mesas are from diapiric domal uplift similar to salt deposits on earth?

VanderL
2004-Feb-12, 01:32 PM
diapiric domal uplift
Don't you need a lot of water to do that kind of uplifting?
And it's the form of the edges of the mesas, the cliffs that I'm referring to.
And could you maybe also link an example? That way Chook (and me too) can still follow the discussion without having to google constantly :lol:
Cheers.

Chook
2004-Feb-12, 06:54 PM
Thanks for the help, not.
I'll go back to the "Unrelated to Space" topics.

VanderL
2004-Feb-12, 07:29 PM
Sorry Chook, there isn't any such topic.
Keep it up, just get used to the jargon and there is always someone willing to explain to us how the Universe works.
Cheers.

Duane
2004-Feb-12, 07:47 PM
damionpaul--interesting question, but on first blush I would say unlikely. Not impossible, but unlikely. The thing is, the process arising from the crustal cracking would be sufficient to explain the raised mesas, especially those which are located in the floor of the valley.

With our current understanding of the processes that gave rise to the Valles, the involvement of diapars is not necessary. While certainly some degree of lift, especially in other parts of Mars, could have arisen as a result of this process, the Marinaris actually shows more signs of shrinkage than lifting. This is partially why it is thought the trench opened for as long and as deep as it did--the shrinkage of the lithosphere combined with the deformation which arose during the formation of the Tharsis Montes and Tharsis Plateau.

Frankly, the final answer will probably have to wait until the area is visited ;)

VanderL--

1) No the rift-like processes on Mars do not appear to be caused by tectonics. There is some certainty here given the lack of subduction zones combined with the stable formation of the Tharsis complex. If there had been tectonic activity, the lithosphere would likely have "drifted" as the plates on Earth do, thereby preventing the formation of the gigantic volcanoes evident on Mars.

Note I call them "rift-like". The process is quite different from the rift processes of Earth.

2) Yes, the process allows for the formation of mesas. An anology might be the way that concrete sidewalks crack as a result of frost. The cracking can split, leaving islands or "mesas" between the halves.

In the case of Mars, the formation of the trench occurred over the course of eons, with there likely being stops and starts, espcially during the initial formation. Add in the the possible erosion from flood water, and the mesas seem to be a reasonable consequence.

3) Yes for the same reasons.

4) It appears the the rifting has stopped, and that most, if not all, of the processes which lead to the lithospheric splitting occurred in the ancient past-- ~ 3 Billion yrs ago. Since then, the dominant process appears to be wind erosion. There is some disagreement here though, as some scientists have postulated that the volcanic process has occurred recently (well geologically speaking, 500 million yrs ago or so) and might even be active today.

Personally, I would tend to doubt those claims, given the cratering count of even the "youngest" areas of Mars, but again we really won't know for sure until measurements are taken on Mars itself.

johnm--Yes that could cause some minor erosion, but it certainly doesn't account for the types of terrain seen on Mars today. Temperature swings are not, in and of themselves, erosional in the absence of something that can melt and refreeze (like water).

Chook--keep pluggin lad, it's not that hard! :P

Chook
2004-Feb-12, 11:31 PM
Quote Duane:
"Chook--keep pluggin lad, it's not that hard!"

Thanks for the encouragement ... it REALLY sounds interesting and I'd love to know what you are talking about but I'm not understanding the key words.

Look - it really would be valuable for all us amateurs, like myself, if there was a reference page here where we could look up specialised words like "valles, lithosphere, diapars (is that the same as nappies?lol), tectonics, subduction zones, mesas, diapiric domal uplifts" etc. etc.

I am quite happy to "Google" these words, as VanderL has suggested - but a resourse such as a Technical Dictionary would be added value to this wondeful forum.

Especially to Beginners, like myself.

VanderL
2004-Feb-13, 06:33 PM
Ok Chook, point taken I'll try to give some links once in a while, and don't think I'm an expert, cause I'm not.

Now this
http://www.spaceref.com/news/viewsr.html?pid=11852
What do the planetary geologists think how these features were created?
Cheers.

Duane
2004-Feb-13, 11:12 PM
VanderL, planetary geologsts think this:


The somewhat concentric bands in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image may be an expression of eroded layered material.

Says that right in the article. Now because that might make me sound like a smart-alec, which I am not trying to be, let me paraphrase.

The picture might show layered material within the crater that has undergone some form of erosion. Because it is Mars, probably wind erosion.

By the way, you'll notice a lot of "mights" and "could be" and "its thought" in posts regarding this type of discussion. The reason for that, is that you cannot be absolutely sure until you have actually stood on the spot and looked really carefully at it. While the formations appear to be similar looking to formations on Earth that were caused by certain processes on Earth, it is not Earth. As such, we can only hypothesize until we get there to look.

VanderL
2004-Feb-13, 11:28 PM
Thanks Duane, that's exactly what I want to hear; the "mights" and "possibly's" I mean, because I think we are projecting too much Earth processes onto Mars and we need a lot more data to be sure.

Btw I heard there's a (Barbie) doll named after you!
Cheers.

Duane
2004-Feb-13, 11:58 PM
Really?!? A Duane doll? :rolleyes:

VanderL
2004-Feb-15, 12:04 AM
Yeah, apparently a Ken replacement!
Cheers.

damienpaul
2004-Feb-15, 12:39 AM
because I think we are projecting too much Earth processes onto Mars and we need a lot more data to be sure. I agree wholeheartedly, but it is hard not to be earth centred in our thinking.

Maybe there aren't any Ken and Duane Martian dolls on Mars...:lol:

Algenon the mouse
2004-Feb-16, 10:41 PM
I am not ready to rule out convections or plate tectonics on Mars. I have heard all the theories before, but I still think that there might be plates on Mars, just fewer of them. Mars is smaller. We actually have no idea what state the lithosphere is in, it is all just guess work and theory. The Volcanos might just be dormant. Their cycle of eruption might be longer than earth volcanos due to fewer plates. Shield volcanos tend to get big, btw. and if it is just a few plates that are seperating...

Until we REALLY look at the geology (marsology?) of Mars, we will not really know.

VanderL
2004-Feb-17, 10:13 PM
Has anyone tried to explain what the sequence of events were that can explain the shape of the Olympus Mons caldera? There are several circles visible, is it possible to deduce which is the oldest eruption (if it erupted at all) and which one is the freshest?

damienpaul
2004-Feb-17, 10:20 PM
And as an extension to your question VanderL perhaps, add in when asteroidal impacts occured.

VanderL
2004-Feb-17, 10:34 PM
You're referring to the small impacts in the sides of Olympus Mons and the caldera I presume?
Those would be the latest addition, because old impacts are presumably covered by lava flows. Btw where are the outflows of lava?
Cheers.

Tinaa
2004-Feb-18, 01:38 AM
Since Mars has an atmosphere, wind erosion would have turned much of that lava to dust after a couple of billion years.

Guest
2004-Feb-18, 08:09 AM
You mean that the last eruption of Olympus is billions of years ago? Wouldn't there be layers visible then, where the erosion exposes the different lava flows, and with a volcanos this size there would be an awful lot of lava to erode, I think.
Cheers.

Duane
2004-Feb-21, 09:22 PM
Algenon the mouse--if there were plates on Mars, there would be evidence of the plates in the form of plate tectonics (http://www.ucmp.berkeley.edu/geology/tecmech.html)--that is, there would be zones of subduction and zones of upwelling. Such zones would be large and fairly easy to see, and no such zones exist on Mars.

Conclusion--plate tectonics are very unlikely to be responsible for the geologic features on Mars.


Has anyone tried to explain what the sequence of events were that can explain the shape of the Olympus Mons caldera?

Yes, several people have. Elizabeth Fuller and James Head of Brown University have suggested there were a series of eruptions through the early history of Mars, starting with the initial flows during the late Hesperion or early Amazonian epoches.

They suggest that the deposits of that early lava seem to have flowed into a broad depression, blocking that depression, which then caused subsequent eruptions to "pool" around newly formed base and flow around the aureole lobes. Subsequent eruptions of magma built apon that base to slowly build the volcano.

In looking at the area around the volcano, or more precisely the aureole lobes formed after the formation of the Amazonis Planitia structure, Morris & Tanaka et al at the University of California suggested in 1994 that the structure is consistant with gravitationally induced collapse. However they also point out that the early history and initial formation of the volcano are hard to identify because the earliest outflows are buried by the subsequent eruptions.

The initial outflows show stratification, suggesting there were several periods of eruption, with the events overlying each other (Peitersen et al, 2001). This stratification also suggests that the initial eruptions were the largest, with subsequent eruptions being smaller, thereby building overtop of each other.

The flows and subsequest collapse appear synonymous with processes on Hawaiian volcanos and islands, although Russel & Head (2001) suggest some of the structure appears consistant with a combination of lava flows and lahars.

Fuller & Head (2003) also note that recent MOLA data reveals discernable flow margins. While this could be the result of ejecta layering, their cohesiveness and differiential weathering make it more likely they are solid rock units.

The caldera was probably formed as a result of episodal eruptions caused by upwelling magma filling the chamber below the volcano. The chamber would fill, the volcano would erupt and empty the chamber, and the ediface would collapse into the voided chamber. The current look of the formation reflects the multiple eruptions and probably also reflects the long-term formation time of the volcano itself. That is, the location of the upwelling magma has not changed over many millions of years.

This is also why some scientists (for example, this article in Space Science News (http://science.nasa.gov/current/event/ast18feb99_1.htm)1999) suggest Mars may still be active. It is possible that the magma which filled the chamber is still viscous enough to refill the chamber.

Again, it is my view this is unlikely, given the presence of impact cratering in the caldera.


And as an extension to your question VanderL perhaps, add in when asteroidal impacts occured.

Crater dating techniques (http://www.adlerplanetarium.org/learn/planets/planetary_geology/crater_dating.ssi) are generally based on assumed fall rates of meteors. Without direct investigation, it is not possible to state with confidence when a single crater appeared.


Since Mars has an atmosphere, wind erosion would have turned much of that lava to dust after a couple of billion years.

Well, not really Tinaa, because Mars's atmosphere is less than 1% of Earth's atmosphere, while there will be some erosion, it is not going to be fast enough to erase features like lava flows, even in the timeframe of billions of years.


Wouldn't there be layers visible then, where the erosion exposes the different lava flows,

Yep! :D

VanderL
2004-Feb-21, 09:57 PM
All right Duane,
Thanks... I guess?
Are there pictures that could show us where the outflows from the caldera are, because I don't see them in these latest images.
How can subsequent eruptions form into the shape we see now? My idea is that one circle means one eruption, but these circles are overlapping, so how can magma pool when there is no wall?

When the magma that pushed the volcano to this massive height is released in only one spot (the caldera), shouldn't there be enormous basaltic flows (maybe like the Deccan traps on Earth)?


In looking at the area around the volcano, or more precisely the aureole lobes formed after the formation of the Amazonis Planitia structure, Morris & Tanaka et al at the University of California suggested in 1994 that the structure is consistant with gravitationally induced collapse. However they also point out that the early history and initial formation of the volcano are hard to identify because the earliest outflows are buried by the subsequent eruptions.
What is an aureal lobe (and while I'm at it what is a lahar)? And what does the remark about the earliest history mean? Is there something missing that is buried, or is there something visible that can't be explained unless something older is buried?
I hope you understand my questions, because I find everything about this volcano very confusing.
Cheers.

Algenon the mouse
2004-Feb-21, 10:05 PM
Originally posted by Duane@Feb 21 2004, 09:22 PM
Algenon the mouse--if there were plates on Mars, there would be evidence of the plates in the form of plate tectonics (http://www.ucmp.berkeley.edu/geology/tecmech.html)--that is, there would be zones of subduction and zones of upwelling. Such zones would be large and fairly easy to see, and no such zones exist on Mars.

Conclusion--plate tectonics are very unlikely to be responsible for the geologic features on Mars.


It does not mean that they do not exsist though. For a long time people did not believe in plate tectonics on earth. It is a fairly new field. Sorry, but I am not ready to discount any theory quite yet. Not all zones of subduction and upwelling are easy to see. We are discovering new ones on earth everyday. I think we need to wait until we get more information and then make conclusions.

damienpaul
2004-Feb-21, 11:17 PM
I am compelled to agree with Algenon the Mouse, wasn't only recently did they discover a rift between India and Australia, effectively splitting the Indo-Australian Plate (I think debate is continuing on this)

http://web.earthsci.unimelb.edu.au/antarct...eTectonics.html (http://web.earthsci.unimelb.edu.au/antarctica/plateTectonics.html)

Some tectonics are extremely subtle. I am not saying yes or no to Martian tectonics, but like Algenon I am not willing to say no until all evidence is presented.

Duane
2004-Feb-21, 11:38 PM
I never said no. I said, and continue to say, unlikely. As has been pointed out, there are tectonic processes even on Earth that are subtle and hard to figure out.

Even though the process has only relatively recently come to be accepted, it is a idea that has been around for at least 3 centuries. In fact, the Dutch map maker Abraham Ortelius suggested as early as 1596 that the continents may have started out as one piece, which then broke apart.

The current theory first gained actual scientific attention as a result of the work of A.L. Wegener in articles he published in 1912. The idea has been considered and explored ever since. The discovery of the mid-ocean ridge in the fifties finally convinced most scientists that the theory had merit, and this produced a flood of research papers starting in the early 60's.

Duane
2004-Feb-21, 11:47 PM
Damien, I'm thinking you might be better qualified to answer VanderL's questions on volcanism?

Algenon the mouse
2004-Feb-22, 06:01 AM
I study and teach many classes on vulcanism and meterology. That is why I am not ready to discount this theory. I agree it is unlikely, but many people could not explain the formation of the coulees in Eastern Washington State until recently. (another fasinating event)We should find out soon if the theory should be discounted entirely.

Just remember that many scientist thought for years that the people of ancient pompeii were killed by ash. It took a geologist to actually study the earth and deteremine otherwise.

VanderL
2004-Feb-26, 06:07 PM
http://www.spaceref.com/news/viewsr.html?pid=11994
Here's another example of a feature that defies logical explanations. Here also there are rounded "cliffs", but they are very steep. This feature is imo only explainable as an electric discharge phenomenon, removing all the material without trace.
Something else in this picture: there is a high incidence of craters with a smaller crater exactly on it's rim. This is a vey unlikely event when you consider impacts, and in this image there are several of them, electrically they make sense, because lightning would strike at the higher points (just as on Olympus Mons?).
Cheers.

Duane
2004-Feb-26, 08:33 PM
Electric universe again VanderL? Is that what all these questions have been about--a way for you to try and advocate a theory that has been, IMHO, thoroughly discredited?

To answer you, there are plenty of perfectly logical explanations for the features in this photograph.

First of all, I suggest you look at what ASU's THEMIS instrument (http://themis.asu.edu/inst.html) does. This image is submitted purely for it's artistic value and has no scientific value what-so-ever.

Why?

Because the image has not been calibrated to remove analmalties nor the defining of the sharp edges due to the imaging team's attempt to appproximate the motion of the Odyssey spacecraft which took the picture.

Furthermore, this is a thermal image. The wave-length used to obtain the image has not been disclosed by the imaging team. Neither has the size of the image been disclosed--is it 100meters? a 1000? More? Less?

As for the "cliffs" as there is no reference to the size of the image, there is also no way to reference relief. Those "cliffs" could be 10 meters or 100 meters high or low.

In fact, the "cliffs" may not be cliffs at all--again, this is a thermal image, so you could be seeing a change in the wavelength between different material. Like, say, heated highland material interspersed with lower-temperature material in the structure looks like something resulting from water run-off.

From your responce, I think you are looking at the branch-like structure as if it was raised. This may simply be an artifact of the camera--the feature might be sunken, or even, or raised, or very slightly up or down, or any of a number of different things. We can't tell, because this is a thermal image.

My point is, you can't take an image like this and make any scientific comment about it, other than how pretty it is , or how it resembles something, because you don't have enough information about the image to make a judgement.

As for this:


Something else in this picture: there is a high incidence of craters with a smaller crater exactly on it's rim. This is a vey unlikely event when you consider impacts, and in this image there are several of them, electrically they make sense, because lightning would strike at the higher points (just as on Olympus Mons?).


Whatever do you mean? Are you suggesting it's not possible for a crater to form on the rim of another crater? Once again, taking into account the fact that we are given no information by which to make judgements about this image (not photograph!), you can't even be sure which of the the craters is the "lower" one.

As for the incidence of overlapping craters, depending on the age of the surface where this image was taken, it could have accumulated impact craters over billions of years. Take a look at the moon--there are craters over craters, over craters. An incidence of overlapping over time is certainly to be expected, in fact I am surprised we don't see more of them.

As for the comment about Olympus Mons, surely you are not suggesting that a 70 or so mile wide caldera is the result of a lightning strike? Or that a single crater on the rim of the caldera suggests something other than a meteor landed there?

VanderL
2004-Feb-26, 10:18 PM
To answer you, there are plenty of perfectly logical explanations for the features in this photograph.


You mean that this image may represent nothing, because it isn't calibrated?



In fact, the "cliffs" may not be cliffs at all--again, this is a thermal image, so you could be seeing a change in the wavelength between different material. Like, say, heated highland material interspersed with lower-temperature material in the structure looks like something resulting from water run-off.

This same imaging technique shows us perfectly "interpretable" craters though.


From your responce, I think you are looking at the branch-like structure as if it was raised. This may simply be an artifact of the camera--the feature might be sunken, or even, or raised, or very slightly up or down, or any of a number of different things. We can't tell, because this is a thermal image.

Nope, I see it as "depressed", a raised feature would be even stranger don't you agree?

As for the craters with small craters on their rims, what I mean is how likely is a meteor strike on the rim of any crater and how often do we see them in reality?


An incidence of overlapping over time is certainly to be expected, in fact I am surprised we don't see more of them.


Exactly!

I'd say that an electric discharge is a common event in the solar system, and imho even if the electric star model is wrong, there can still be discharges responsible for planetary features. And when an idea is discredited or unlikely, it still doesn't equate to being untrue, only evidence counts and whenever I see something strange I'll ask questions. And why not? Any correct model should explain everything we see, so if I ask these questions and they are explained by whichever model that explains it all, Im happy to have learned what there is to learn.
Hope you're not offended by my constant questioning and referring to discharges;, electrical scarring is the only other way that I see that could explain these features. I hope to discuss many more strange images.
Cheers.

damienpaul
2004-Feb-27, 08:32 AM
From a volcanology point of view - I am looking at a large version of a shield volcano such as those in Hawaii, with multiple craters and collapse features as well as subsidary craters. Are there any Volcanologists here that might want to add to this, or to correct this if needed.... I am keenly interested in Alympus Mons.

Duane
2004-Feb-27, 06:45 PM
You mean that this image may represent nothing, because it isn't calibrated?


No, I mean that you cannot make scientific observations in the absence of a frame of reference. It represents "art" as defined by the members of the THEMIS imaging team.


This same imaging technique shows us perfectly "interpretable" craters though.


Sorry VanderL, I'm not sure what you mean by this. The imaging technique will allow for interpretation once the image has been correctly calibrated and it's reference points given.


a raised feature would be even stranger don't you agree

Depends where it is. If it was a basaltic lava flow, I would expect it to be raised. Same if it was a mud flow, or a lahar, or even a pyroclastic flow. Again, you can't make a judgement like that in the absence of a reference point.


As for the craters with small craters on their rims, what I mean is how likely is a meteor strike on the rim of any crater and how often do we see them in reality?


They are as likely as an asteroid hit on any other part of the surface. In reality, we see them quite often, on every geologically older body in the solar system.


I'd say that an electric discharge is a common event in the solar system, and imho even if the electric star model is wrong, there can still be discharges responsible for planetary features.

On what basis to you make this statement? Can you provide any evidence for such an event, other that your opinion that a certain feature "looks like" it arose from such a strike? Quite frankly VanderL, if the "electric sun" model fails, so does the "electric solar system".

It seems to me that if an electrical discharge of the size needed to cause a 1000KM (or even 100KM) long "fissure" had occurred, there would be evidence of a buildup of charge somewhere in the solar system even now. Yet there is no such evidence, anywhere. How can the electric model of the solar system explain that?

I am absolutely not offended by ongoing questions. I enjoy discussing the features, their causes, the theories that are offered to explain them, etc. I am, however, offended when you frame your questions in a manner that suggests only your explanation can be correct. Furthermore, I have a great deal of difficulty with the suggestion that current models of the universe, stars, planets and the like are wrong without a clear argument expousing why they are wrong.

This is especially true when the evidence used to support such an argument is shown to be incorrect time and time again. By all means, ask your questions--but spend a little time to review your assumptions before you state them as "fact", take the time to consider other possibilities as to cause before you decide what caused them, and keep an open mind to the possibility that the theories currently in place do explain the features we see with some degree of accuracy. This comment:
electrical scarring is the only other way that I see that could explain these features. is an example--it is not the only explanation, it is just one that you like.

I will say this--your questions certainly make me review my opinions, so keep them up. Just take a little time to research what you are asking before you ask.

damienpaul
2004-Feb-28, 05:35 AM
QUOTE
a raised feature would be even stranger don't you agree



Depends where it is. If it was a basaltic lava flow, I would expect it to be raised. Same if it was a mud flow, or a lahar, or even a pyroclastic flow. Again, you can't make a judgement like that in the absence of a reference point.


Raised features occur everywhere across the Earth, as I stated earlier, this could be the result of a collapse feature due to the eruptive material drying up or being totally evacuated from the vent. I'd be very interested to see if there were evidence of breccia in the cone of Olympus Mons.

Are there any images of fissuring and parasitic cones which would not be surprising but interesting.

Duane
2004-Feb-29, 10:23 PM
Good question dameinpaul. I found this on a quick search through the GEOKEM site:


There are some major faults and rifts and a few volcanoes of basaltic appearance, some of which are surprisingly large. Olympus Mons is 550km in diameter and 25 km high with half a dozen overlapping calderas at the summit, and one or two flank parasitic cones

so I am guessing there are images showing the cones, although I haven't tried very hard to find any. Could probably find some on one of the Mars image sites.

DeanKennedy
2004-Sep-12, 08:01 PM
Came here looking for comments on the cliffs of Olympus Mons. They look like the cliffs might have been underwater once, but that doesn't seem to be a popular explanation. General comments, please? And links for further information?

Algenon the mouse
2004-Sep-13, 01:40 AM
There are areas that look like they have been eroded by water. It was definitely not a basalt flow erosion. I have a strong feeling that it more likely that it was eroded by wind and compacted ash. It was probably transported in a cloud of hot firey gas called a nuée ardente or a pyroclastic surge. (I think I spelled it right. spelling is not my forte). The erosion looks very similar to other surges on earth like that of pompeii and mount pelee. If this is the case, it would have been a bad day to be on Mars when it happened.


I could be wrong though...anyone else have any thoughts?

VanderL
2004-Sep-13, 08:53 PM
Came here looking for comments on the cliffs of Olympus Mons. They look like the cliffs might have been underwater once, but that doesn't seem to be a popular explanation. General comments, please? And links for further information?

I you're right those cliffs must have been under water when the volcano was not as high (or we had us some very high oceans). I guess it could have been under water, although the features of the cliffs in the images look more like they were generated by "leaking" (heh) of melting ice, because the starting points are not on the plateau but just below the rim as is thought to have happened in crater walls and channel walls all over Mars.

Since the Mars mission everybody has been waiting for evidence of water, unfortunately the water itself seems to be gone and the traces are difficult to find. Seems as if the evidence of Martian rivers and oceans (even the ancient ones) is completely erased.

Cheers.