Surface H2O on Mars for Eons - New Scientist

Rxke · 2004-07-20 13:57:27

http://www.newscientist.com/news/news.j … 996178]New Scientist

Allrighty!
Opp.'s latest findings suggest standing water, not for short periods, but for eons...

Making life even more probable than thought before... -again-

Boyboyboy, S&O, in combination with the orbiters are really redrawing the picture lately, ain't they?

... Shaun, your paradigm-shift is starting to make serious rumbles!

Palomar · 2004-07-20 15:40:33

"The new discovery, reported by NASA's Jet Propulsion Laboratory on Friday, pushes the boundaries significantly further back, into geological timescales...

The actual time span has not been estimated, but it reveals enough time to strengthen the possibilities that life could have evolved on Mars. The team is expects to spend most of this week analysing the razorback with the rover's various spectrographs."

*Okay: But they're still going with the solitary event -- a "single wet episode" scenario, right? Seems so; article refers to "time span" (singular).

Oh now I'm really wondering about FOSSILS!! :band:

How long will we have to wait for a fossil-hunting expedition?? :-\ Preferably via humans of course!

--Cindy

P.S.: Blue looks really lovely on Mars. It'll be a favorite color there, I'll bet. :;):

RobS · 2004-07-20 16:25:45

A single cracked rock filled with a deposit left by a fluid tells us at minimum of a single event involving the fluid. It could tell us of multiple fluid events, but I doubt with the rover we can gather the evidence to detect multiple events of water flowing through this crack.

The important point, though, is that the rock formed in water, then lithified--it became hard--then it cracked, then the fluid flowed through the crack. If the sediments had cracked shortly after formation they would not have had time to lithify and thus would not have formed a permanent crack; they would have slumped back together and healed the crack. So the vein tells us the water reappeared a long period of time after it was first there. That's the significance of the discovery, according to the article.

-- RobS

Shaun Barrett · 2004-07-20 17:14:12

Those MERs are wonderful machines all right!
They're certainly giving us many more pieces of the martian jigsaw puzzle to play with but, as RobS tells us, we have to be careful not to over-interpret the data. I confess to being a bit of a romantic when it comes to Mars and so I have to keep my enthusiasm in check somewhat!

Thanks, Rik, for the encouragement about paradigm shifts. I hope any actual shift won't just move us from one stage of frustrated puzzlement to another!
That's the trouble with robotic probes; they usually present us with more questions than they answer. If we had humans there, we could modify our 'interrogation' of Mars as we went along, changing the emphasis of the exploration as circumstances dictated.

I'm still confused about the paradox of a planet which shows so much evidence of massive inundation all over the place and yet has so many areas of olivine on the surface. (Olivine, as you know, is extremely vulnerable to quick weathering in the presence of water, or even ice.) So, while every report about surface water makes me wonder whether one of the MERs might actually stumble across a macroscopic fossil (Yes, wouldn't it be fantastic, Cindy?! ), the wet-Mars/dry-Mars inconsistency keeps pulling me back, like the bridle on a horse!

Still, Spirit and Opportunity aren't dead yet and I'm optimistic, as always, that great discoveries are just around the corner.

Rxke · 2004-07-20 20:26:08

I'm hesitant to bring this up, but, who knows.. At lookout point, Spirit wil be able to see that dark spot, wich some people have claimed might be a cave, or even an ancient aquiefier-flowout....
Now wouldn't that be something?

Palomar · 2004-07-21 05:00:12

I'm hesitant to bring this up, but, who knows.. At lookout point, Spirit wil be able to see that dark spot, wich some people have claimed might be a cave, or even an ancient aquiefier-flowout....
Now wouldn't that be something?

*Yes. I've been wondering about Marsian caves for a while. Thank god the MERs have gone this long. Hopefully they can and will function another 6 months at least. :up: The aquafier flowout scenario would be great too, of course.

--Cindy

C M Edwards · 2004-07-21 15:23:10

When exposed to carbonated water, olivine slowly breaks down to form other iron bearing minerals, like the hematite scattered all over Mars.

How could the two coexist in the forms seen by Opportunity, over the apparent timescale observed? You've got me.

rgcarnes · 2004-07-23 08:20:56

"Apparent Timescale" is the key pair of words. Not everything in a sensor's "view" has to have been produced at the same time, although there is strong incentive to make that assumption in order to seek simplicity. It is still just an assumption.

Please forgive me for stating what may be obvious, but the fact that it is difficult to reconcile may mean that it is not a valid assumption.

EarthWolf · 2004-08-06 14:04:39

Hello,

So then, it appears that Mars may have had extensive lakes or a massive ocean? Does this lend support to the long wet model of areology?

Cordially,

EarthWolf

atomoid · 2004-08-11 01:57:12

Does the "Olivine problem" really preclude long periods of water? the more i read, the less im convinced of that.
http://mineral.galleries.com/minerals/s … e.htm]some data on Olivine

Olivine is found in ultramafic igneous rocks and marbles that formed from metamorphosed impure limestones. Mafic is a word that is used to define igneous rocks with a high iron and magnesium content. The "MA" is for magnesium while the "F" is for ferrum, the latin word for iron. The olivine minerals have a high melting point and are the first minerals to crystallize from a mafic magma. Forsterite crystallizes first with fayalite crystallizing last when other minerals such as the pyroxenes are just beginning to form. The early crystallization of olivine is the reason that molten lavas can contain already crystallized grains of olivine. Some ultramafic rocks can be composed of almost all olivine and these are called dunites or peridotites. Peridotites contain the same chemical makeup as the molten magma in the Earth's mantle. Thus peridotite could be called the most common rock by volume in the Earth, although on the Earth's surface and in the crust it is not nearly as well represented.

heres an http://www.psrd.hawaii.edu/Nov03/olivine.html]article about Olivine on Mars in which it states:

Like other silicate minerals, olivine is susceptible to chemical weathering in the following ways: dissolution (minerals dissolve in water), hydrolysis (minerals react with water forming clays), and oxidation (iron-bearing minerals react with oxygen forming iron oxides or rust). The chemical reactions occur only where the surface of the mineral and water interact.
...The reality of how susceptible olivine is to chemical weathering does not seem to jive with its appearance on the Martian surface. Some alteration minerals have been identified in TES spectra of the Martian surface, but not necessarily in the olivine-bearing regions. So, the presence of olivine in places such as Nili Fossae and Ganges Chasma apparently without a corresponding abundance of alteration products seems inconsistent with what we know about how fast olivine weathers. There is a demonstrated need to better understand and quantify how long olivine has been exposed on the surface.
--- The discovery of olivine-bearing rocks on Mars underscores the need to understand weathering rates of silicates in the Martian environment.

Well, it sounds like a few main Olivine caches exist mainly i Ganges Chasma and Nili Fossae, but since theres not much free oxygen or water to weater it away into rust or clays, any erosional releases from these caches should stick around for quite a while, so its apparent concentration in any area could build up as wind erosion continues.

On the flip side (and maybe i'm missing the real crux of why Olivine is expected to be so rare on Mars), doesn't the argument that Mars Olivine is so unexpected also beg the question that we shouldnt be seeing any Olivine on Earth either since its always so wet here, but Olivine isnt exactly uncommon is it?

Shaun Barrett · 2004-09-22 21:42:50

Not sure how I missed this post of yours, Atomoid, but your comment about olivine managing to remain unaltered even here on Earth is a very interesting point.
A little googling revealed that accessible sources of olivine are rare on Earth, as you would expect, because of their susceptibility to weathering by water; rare but NOT ABSENT! Outcrops are only found in the driest of areas, such as Zagbargad Island, in the Red Sea, and Arizona.
But, as for Mars, it occurred to me that massive weathering of olivine could indeed have occurred during the warmer wetter intervals in its history. I can imagine deep deposits of olivine weathering into clays etc. at the surface, and underground at the periphery of the deposit, where water has access to it. I can then imagine those weathering products being removed by aeolian erosion in drier spells, revealing unaltered olivine once more.
In addition, perhaps more frequent volcanic activity than Mars is given credit for, even into quite recent times, has produced fresh supplies of olivine at the surface. Even allowing for recent episodes of 'wet weather' on Mars, presumably there would still be significant unaltered deposits here and there on the surface, which is what we're seeing.

Thanks, Atomoid, for triggering this cascade of speculation on my part! I appreciate your response to my comments on the apparent contradiction of evidence of large amounts of water on Mars and the existence of significant quantities of olivine, a problem which has bothered me for some time. Your input is serving to make it less of a problem!

C M Edwards · 2004-09-23 17:49:58

Could Mars have clay?

atomoid · 2004-09-29 19:02:54

i googled a couple old pages about Kaolinite, http://marsrovers.jpl.nasa.gov/fido/sol … .html]clay
and this about http://speclab.cr.usgs.gov/PLANETARY.ab … html]where is Mars' clay?

REB · 2004-11-11 12:41:54

http://www.nfinity.com/~exile/marsweather.htm]Good information on the Hellas Basin

From the webpage;

"Because of its latitude and great depth, it seems likely that there is an abundance of water ice under the surface in the Hellas Basin. Mossbaur spectra, which can detect the presence of hydrogen, suggest that, except for the poles, this may be one of the "wettest" places on the planet. It may possibly be the last place where liquid water ever existed on the surface of Mars. In mid summer, it is one of the "garden spots" of the whole planet, with atmospheric pressure of over 10 millibars, more than twice what it is at the mean planetary horizon. Since the vapor pressure of water is lower than 10 millibars if the temperature is less than 60 deg. F (16 deg. C)(4), this may be one of the few places on the planet where any water on the surface will not immediately boil away. The days are long and relatively warm, and the nights are fairly mild, considering how far north the Hellas Basin is located."

REB · 2004-11-11 12:53:27

http://www.msss.com/moc_gallery/r10_r15 … .html]This MOC picture is taken near the low end of Hellas. Notice the muddy appearence of the area, and what looks like a flooded area near the center of the picture.

This could be a slushy type ground simular in texture to what they are expecting on Titan.

I would love to see a MER here.

REB · 2004-11-11 12:58:14

http://www.msss.com/moc_gallery/r10_r15 … .html]More here. Something is keeping a young surface in Hellas.

Rxke · 2004-11-11 13:24:20

and with the 'traveling poles' there might be quite a bit of ice trapped between layers upon layers...

The plot thickens...

New Mars Forums

Announcement

#1 2004-07-20 13:57:27

Re: Surface H2O on Mars for Eons - New Scientist

#2 2004-07-20 15:40:33

Re: Surface H2O on Mars for Eons - New Scientist

#3 2004-07-20 16:25:45

Re: Surface H2O on Mars for Eons - New Scientist

#4 2004-07-20 17:14:12

Re: Surface H2O on Mars for Eons - New Scientist

#5 2004-07-20 20:26:08

Re: Surface H2O on Mars for Eons - New Scientist

#6 2004-07-21 05:00:12

Re: Surface H2O on Mars for Eons - New Scientist

#7 2004-07-21 15:23:10

Re: Surface H2O on Mars for Eons - New Scientist

#8 2004-07-23 08:20:56

Re: Surface H2O on Mars for Eons - New Scientist

#9 2004-08-06 14:04:39

Re: Surface H2O on Mars for Eons - New Scientist

#10 2004-08-11 01:57:12

Re: Surface H2O on Mars for Eons - New Scientist

#11 2004-09-22 21:42:50

Re: Surface H2O on Mars for Eons - New Scientist

#12 2004-09-23 17:49:58

Re: Surface H2O on Mars for Eons - New Scientist

#13 2004-09-29 19:02:54

Re: Surface H2O on Mars for Eons - New Scientist

#14 2004-11-11 12:41:54

Re: Surface H2O on Mars for Eons - New Scientist

#15 2004-11-11 12:53:27

Re: Surface H2O on Mars for Eons - New Scientist

#16 2004-11-11 12:58:14

Re: Surface H2O on Mars for Eons - New Scientist

#17 2004-11-11 13:24:20

Re: Surface H2O on Mars for Eons - New Scientist

Board footer