From NASA’s Jet Propulsion Lab, some exciting news of the “picture is worth a thousand words” variety – NASA Rover Finds Old Streambed on Martian Surface
Scientists are studying the images of stones cemented into a layer of conglomerate rock. The sizes and shapes of stones offer clues to the speed and distance of a long-ago stream’s flow.
“From the size of gravels it carried, we can interpret the water was moving about 3 feet per second, with a depth somewhere between ankle and hip deep,” said Curiosity science co-investigator William Dietrich of the University of California, Berkeley. “Plenty of papers have been written about channels on Mars with many different hypotheses about the flows in them. This is the first time we’re actually seeing water-transported gravel on Mars. This is a transition from speculation about the size of streambed material to direct observation of it.”
The finding site lies between the north rim of Gale Crater and the base of Mount Sharp, a mountain inside the crater. Earlier imaging of the region from Mars orbit allows for additional interpretation of the gravel-bearing conglomerate. The imagery shows an alluvial fan of material washed down from the rim, streaked by many apparent channels, sitting uphill of the new finds.
The rounded shape of some stones in the conglomerate indicates long-distance transport from above the rim, where a channel named Peace Vallis feeds into the alluvial fan. The abundance of channels in the fan between the rim and conglomerate suggests flows continued or repeated over a long time, not just once or for a few years.
The discovery comes from examining two outcrops, called “Hottah” and “Link,” with the telephoto capability of Curiosity’s mast camera during the first 40 days after landing. Those observations followed up on earlier hints from another outcrop, which was exposed by thruster exhaust as Curiosity, the Mars Science Laboratory Project’s rover, touched down.
“Hottah looks like someone jack-hammered up a slab of city sidewalk, but it’s really a tilted block of an ancient streambed,” said Mars Science Laboratory Project Scientist John Grotzinger of the California Institute of Technology in Pasadena.
The gravels in conglomerates at both outcrops range in size from a grain of sand to a golf ball. Some are angular, but many are rounded.
“The shapes tell you they were transported and the sizes tell you they couldn’t be transported by wind. They were transported by water flow,” said Curiosity science co-investigator Rebecca Williams of the Planetary Science Institute in Tucson, Ariz.
The science team may use Curiosity to learn the elemental composition of the material, which holds the conglomerate together, revealing more characteristics of the wet environment that formed these deposits. The stones in the conglomerate provide a sampling from above the crater rim, so the team may also examine several of them to learn about broader regional geology.
The slope of Mount Sharp in Gale Crater remains the rover’s main destination. Clay and sulfate minerals detected there from orbit can be good preservers of carbon-based organic chemicals that are potential ingredients for life.
“A long-flowing stream can be a habitable environment,” said Grotzinger. “It is not our top choice as an environment for preservation of organics, though. We’re still going to Mount Sharp, but this is insurance that we have already found our first potentially habitable environment.”
During the two-year prime mission of the Mars Science Laboratory,esearchers will use Curiosity’s 10 instruments to investigate whether areas in Gale Crater have ever offered environmental conditions favorable for microbial life.
NASA’s Jet Propulsion Laboratory, a division of Caltech, built Curiosity and manages the Mars Science Laboratory Project for NASA’s Science Mission Directorate, Washington.
For more about Curiosity, visit: http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl .
You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity and http://www.twitter.com/marscuriosity .
============================================================
If Curiosity finds some gold in that old stream bed, you know there will be a manned mission to Mars…gold fever and “go fever” are two strong forces for accelerating exploration, combined they’ll be irresistible.
Böehm, you are the bomb !!
It seems to me that since the water flow velocity is from the potential energy available (mgh) and g on Mars is about 1/3 of g on earth then the slope ( available h) must be about 3 times greater on Mars to get the same velocity.
A conglomerate is the worst kind of sediment for fossilized remains.
Oh, come on , they don’t think we’re gonna fall for a cheap trick photo like that , do they?
http://i45.tinypic.com/sey39y.jpg
Ursa Bogus was more convincing.
@Mike McMillan
Mars’ water seems to be all locked up under the surface. Likely this was a aquifer spring. It’s near a volcanic mountain (I believe), so the water might have been heated and forced above the surface back when the volcano was active. Now, it’s all dead.
That may be, but I’m pretty sure I see embedded bits of sea shells in the Earth gravel. Would not moist gravel on Earth contain thriving colonies of bacteria, amoebas, and other life forms. Seems like microscopic examination might be worthwhile, but I am certainly not an expert, of any sorts. GK
This is one of my favorite images from Mars.
From Opportunity at Cape St. Vincent, Victoria Crater. June 28, 2007, Sol 1167.
The link is to a medium resolution 126K image, heavily color enhanced.
There is lots of cross bedding, angular unconformities marking several depositional and erosional events. Squyres thinks it is eolian and he is the expert. (Note well Figs 4 and 8.)
But I can make a case that the thick, cross bedded body(s) are part of a point bar sandstone (river) deposit with at least one “U” shaped scour mark at the base of some units. (right hand side of the outcrop). The scours would argue for a fluvial environment.
I’ve had great fun showing it to geologist and geophysicist friends asking them to guess where it is from.
As a geologist, I agree that the potential rounding of the pebbles/gravel can indeed be aeolian in origin. Indeed, if surface storms/winds are/were possible with Mars past atmosphere they could cause such weathering.
The photo shows very little of any potential depositional process(es) and it is that which really defines the water/air difference.
On the reasonable assumption that the concrete like conglomerate is the source of the pebbles, we have to ask what cause the pebbles to ‘erode’ out of the conglomerate. Logically in the current Mars environs, we could expect this to be ancient aeolian (from past atmosphere)? – but it could also be caused by some form of solifluction/thermal expansion and contraction process?
My comment (curiously the first?) was written because in order to have a ‘cemented’ or ‘bound’ conglomerate as suggested by the picture – you would have to have some fluid based depositional or evaporative process to enable mineralisation ‘around’ the pebbles (however they were rounded).
hope that makes sense to non-geology types!
In summary, more data/photos is/are required!
regards
Kev
At what temperature is carbon dioxide a liquid? I ask this because it seems like I read that Mars has CO2 ice caps. Mars further away from the sun than earth and thus colder. I would think any water would always be frozen on the planet. So where did the water go? I really am just wondering if the rivers weren’t water rivers but some other gas in liquid form, such as carbon dioxide. I really don’t know, but I do think it is a big assumption to say what the rover sees was caused by a water river.
Stephen, indeed. Having said which, this week’s images from Mars are – frankly – amazing. I suspect many fascinating things are to come. The nature of the mineralogical weathering – and indeed the mineralogy of the cement – are big questions to which we may get answers….
I’ve seen similar transitions in post-glacial-max alluvial systems in which I have dug gold – Afon Wen in N Wales is a classic in terms of its sedimentary history – glacial, fluvioglacial and post-fluvioglacial and that is simply a record of the last deglaciation!
Off to bed though – cheers!
The pictures are similar, but it seems a tremendous leap to conclude the Martian picture could only formed by a long running stream of water. I’m skeptical.
The first thing to note is that you’re viewing an unconformity, and processes that took place during two different periods of time. The pebble circled may, or may not have originated from the consolidated bed on the right. The bed on the right is an outcrop of a cemented matrix pebble conglomerate. This implies that it was transported, deposited, buried, compacted, and cemented while saturated with water.
It has now been exposed to the surface either through uplift or erosion of the overlying beds. The pebble circled is either a product of erosion, or exfoliation of the pebble conglomerate, or a transport from a separate source.
The shadow beneath the outcrop shows that the conglomerate bed has been eroded and undercut by either wind or water, and the circled pebble a product of that erosion.
Anything that moves one solid against another will put wear on those solids and so “smooth” them. We know there is wind on Mars. We know there is fine dust on Mars.
Do we knowthere is something else on Mars that could have smoothed that pebble? Not yet. More data is needed before a conclusion is possible.
(Maybe the next “Curiosity” should include a microscope instead of catnip?8-)
alexwade,
On Earth, CO2 deposits directly to a solid at temperatures below −78 °C and the solid sublimes directly to a gas above −78 °C. Mars is lower pressure, but probably still does sublimation/deposition on Mars (need more pressure for liquid state, not less).
Too cold for liquid water, too little pressure for liquid CO2. The volcano idea sounded possible to me. Might make it warm enough to make a water river for a while.
The conspiracy talk here really scares me. Exactly why should we suspect NASA would be faking martian geology pictures?
alexwade says:
September 28, 2012 at 11:47 am
At what temperature is carbon dioxide a liquid? I ask this because it seems like I read that Mars has CO2 ice caps. Mars further away from the sun than earth and thus colder. I would think any water would always be frozen on the planet. So where did the water go? I really am just wondering if the rivers weren’t water rivers but some other gas in liquid form, such as carbon dioxide. I really don’t know, but I do think it is a big assumption to say what the rover sees was caused by a water river.
=======================================================================
I can’t answer your question but I can offer some information.
http://en.wikipedia.org/w/index.php?title=File:Carbon_dioxide_pressure-temperature_phase_diagram.svg&page=1
This is a chart of the “triple point” of CO2. Under certain condition of pressure and temperature CO2 can be a gas, a liquid or a solid. I do not know if the conditions on Mars would allow CO2 to be a liquid. It has a low enough temperature at times. I don’t know about the pressure but I assume the pressure would be higher in lower areas such as craters and valleys.
Of course wind could have played a role (roll?) in shaping the rocks, but not in creating either the channels or the alluvial fan.
It is my opinion that there is some cosmic force – either undetected, or whose effect is unrecognized – that is responsible for significant (climatic) changes on Earth and Mars (and probably other cosmic bodies, as well) ; a kind of Deus ex Machina, or, Opprimere ab Aethere (Force from the Aether), if you will.
Paul Marko says:
September 28, 2012 at 12:02 pm
”The first thing to note is that you’re viewing an unconformity” – not necessarily, the conglomerate could simply be an evaporitic ‘surface’ crust of the main deposit?
KevinM says:
September 28, 2012 at 12:19 pm
alexwade,
”The conspiracy talk here really scares me. Exactly why should we suspect NASA would be faking martian geology pictures?”
why not – they like to fake earth temps – well, at least adjust them without apparent reason!
one other thought occurred to me – based on the ‘theory’ of possible remnant martian water frozen below the surface – and that would be the heat of an impact object, locally freezing water to allow a localized temporary water ‘source’?
with apologies to the League of Gentlemen! (Brits only I guess?)
KevinM says:
September 28, 2012 at 12:19 pm
Careful – CO2 sublimation (just like water frost and sublimation) depends on the partial pressure of the CO2 (or water). One of the biggest battles at WUWT was on the question does CO2 frost occur at Vostok Station in Antarctica.
Water vapor does not deposit as frost at say -10°C unless the dewpoint (frostpoint, actually, it’s a little different!) is also at -10° C or higher (supersaturated).
Today. Mars likely had a thicker atmosphere a billion years ago. I don’t know how thick or what the composition was.
CO2 cannot exist at any temperature below 5 atm
http://stevengoddard.files.wordpress.com/2011/08/co2_phase_diagram.gif
So if mars had an environment that could allow for liquid CO2, a thicker atmosphere than Earth is likely to have had at least since the Cretaceous, then I think it likely that liquid water would be likely. Theoretically, it is possible to have liquid CO2 and no liquid water, But it must be in high pressure > 5 atm, high CO2 concentration and between -56 and 0 deg C.
Kev-in-Uk says:
September 28, 2012 at 1:14 pm
Paul Marko says:
September 28, 2012 at 12:02 pm
”The first thing to note is that you’re viewing an unconformity” – not necessarily, the conglomerate could simply be an evaporitic ‘surface’ crust of the main deposit?
If so, it’s not obvious from a photo. At least, we’re both talking about water.
Kev-in-Uk says:
September 28, 2012 at 1:19 pm
typo, sorry, should be locally unfreezing trapped water
One thingwe we need to know is this: what are the pebbles made of? If they are made of sedimentary rocks the chances are that they are water derived. If they are made of igneous rocks they may very well be of volcanic origin – but they could still be volcanic rocks reworked in a fluvial environment. We also need to know the gross morphology of the conglomerate bed: the shape of the bed will help us to figure out its origin.
This is an extremely fascinating subject. I made a post on Facebook in which I said that I would love to be the first geologist on a field trip to Mars. This suggestion was poo-pooed by one of the very few conspiracy theorists I know…
I’ve had another look at the photo and I’ll write more later. There is so much to see. I’ll have more time over the weekend.