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 .
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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.
Carsten Arnholm, Norway says:
September 29, 2012 at 3:08 am
Gotta run… dog walk.
Methane is one thing, oil is another. http://www.oilonmars.blogspot.no/ notes:
Abiotic oil is one of the hot buttons on WUWT, there are a couple decent discussions that kind of match the above quote – i.e. don’t expect to find commercially useful amounts. While that salt dome looks like an interesting place for a rover to check out, it may be more interesting for confirmation of processes on Earth rather than turning everything upside down.
Could Mars have its own long-cycle form of ice ages and interglacial periods of outwash? This site is nowhere near the polar regions but interglacial epochs could have various outflow flow effects in different areas. A Mars glacial cycle might even be localized and not hemispheric.
“Curiousity” landed in an impact crater, right? The impact would have pulverized a lot of material and moved it very quickly. Maybe even melted some of the rock. Might the streambed be the result of that impact along with wind erosion?
Also, is the mountain a volcano? What would a pyroclastic flow be like on Mars?
Again, just asking questions as they occur to me.
The binding cement or matrix is virtually impossible to assess from visual inspection of a photo! In simple sedimentology terms the matrix/cement can only come from a few possible sources:
1) immersion/mixing of the pebbles in an already soft fine ‘ooze’ – kinda like a mud, this then dries and binds the pebbles together. Other processes, such as burial and hence overburden pressure and geothermal heat can be involved in the drying/compaction process.
2) Passing of mineral rich waters (usually hot) though the pre-existing gravel and depositing minerals as the ‘cement’ – think of an old chemistry set where you used to make alum crystals from over saturated solution…..or perhaps you can think of Yellowstone park and the hydrothermal springs and the sulphur deposits they create?
3) Grinding of material together, during transportation via water(or ice – e.g. glacial tills), creating finer material which ‘settles’ around the pebbles when it stops ‘flowing’ and remains after drying out.
4) an evaporative process whereby as evaporation occurs near the surface of a deposit, the mineral salts are left behind – forming the matrix/cement – think of salt flats!….
can’t think of any others at the minute – but it has been 30+ years!
I’m sure other Geos will want to chime in!
I’m ignoring any igneous possibilities, but 2) can be related to volcanic/igneous sources.
Any Electric Universe theorists on here? I am not a scientist but in that theory, electrical arcing could explain the “riverbed” like phenomenon on the surface I think.
Gunga Din says:
September 29, 2012 at 10:23 am
Instead of asking questions as they occur to me, you would do well to go learn something about the Curiousity mission directly. If you had done that, you would have learned that Gale Crater is a) large, b) is an impact crater and c) like many large craters has a mountain in the center from the rebound of the impact.
Gale crater is not a volcanic crater.
Please go to http://mars.jpl.nasa.gov/msl and read everything there.
Interesting photos. I’m glad they are releasing this stuff for us to speculate about! Here’s my two cents
My first impression was that the cemented material looks like a layer of caliche cemented gravel similar to what we find near the top of the capillary fringe in arid climate unconsolidated sedimentary deposits here on earth. This possible origin raises questions about the differences between the condition of the depositional environments on Earth and Mars. Differences include changes in the depth within the soil profile where evaporation of water occurs because of the lower atmospheric pressure and the lower relative humidity. Also the lack of water rain would preclude futher concentration of the water souble cementing materials into a narrow horizon.
Saying a soil or rock is of sedimaentary origin does not necessarily imply aqeuous deposition. Other mechanisms include deposits originating from explosive volcanic or impact events, also aeolian deposits, and deposits that are the result of gravity driven mass movements, to name a few.
The loose appearing gravel below appears to have the same provenance as the clasts in the cemented material. This could imply that a process similar to weathering here on earth occurs on Mars. However, weathering on earth is largely involves hydration and oxidation processes
that cause changes to the overall rock and constituent minerals as the it attempts to achieve equilibrium with surface conditions. On Mars, the impact of differential thermal expansion and
contraction would be greater because of the larger range of surface temperatures.
The slightly zoomed out photo (previously linked) shows a little more of the surroundings. But, an even more zoomed out photo that shows the locality on an outcrop scale is needed to put the conditions in context.
Just a couple thoughts to have some fun with!
Looks like the pictures were taken fifty feet apart. The one on the right could have been taken anywhere with a calcium groundwater. My best bet for the one on the left is the Moenkopi Formation in Southern Utah, or maybe the Carmel or Somerville.
richardscourtney says:
September 28, 2012 at 6:52 am
Kelvin Vaughan:
Please explain your ridiculous comment at September 28, 2012 at 6:45 am which has no relationship of any kind to my post which you cite.
Richard
Richard
My point is that it practical experience is far better than to sit in an office and theorise about that which you have no practical experience. How many times have you heard scientists say “we were amazed to find that” which is a feeble way of saying we were wrong but we are not going to admit it!.
Kelvin