Ed's pan makes Fark's Geek tab

Good eye. That is a fascinating rock. That kind of geometry is somewhat unique, so I think you are correct in your suspicion that it says something about the rock's origin. I was thinking maybe a basaltic lava with pahoehoe structure, but the scale seems too small, unless the lava was very fluid.

Sure looks like one! A different take on this anaglyph:


(The baseline shift is somewhere in this off-angle, kind of eyeballed it, made it much less headache inducing!)

Just one more for tonight. Another take on this wondrous structure:



(Also makes for a passable flicker GIF.)

That is truly amazing!

Sort of like bread dough.

CheMin X-ray diffraction results. Feldspar, pyroxenes and olivine detected.
http://www.jpl.nasa.gov/news/news.php?release=2012-341

Bread eagerly eaten by a patient but persistently peckish Mars, deftly depositing dangling duricrust details. i like FredK's brutal x-eye version

To continue the food theme, in today's telecast they described the surface crust layer and showed how part of it had collapsed into the scoop bite mark. Someone watching the telecast with me exclaimed "crème brûlée!"

Reminded me of when the Huygens probe landed on Titan with its surface probe, the initial analogy was crème brûlée, although I think they changed that later.

Interesting that they said they're getting closer to being able to come up with a recipe for Mars sand--feldspar, olivine, pyroxine, plus some amorphous ingredients to be named later. Should beat Space Sand from Amazon.

hmmm.. the 'closest thing to sand on Mars' i wonder if the 'real' sand on mars, if temp/pressure are roght could 'get wet'.. or may there be some resistance imparted by the chemistry?

back in the day, i remember daydreaming about pouring a glass of water out onto the soil of the Meridiani plains to actually 'see what happens' as it happens and then relegating myself to hoping they would someday integrate water and assorted reagents for the sample chamber to run soil chemistry tests without ruining it. i guess im getting a bit closer to that if DuneCraft gets a new recipe and I get around to installing a refigerated vacuum chamber at home.

So, there's a significant feldspar content in the ubiquitous Martian dust, eh? It will be interesting to see if we find source rock that is anorthositic, or source rock that is granitic.

Or both.



-the other Doug

Another interesting moment in the telecon was courtesy of the reporter Craig Couvault, who asked if they had discovered methane. There was a little buzz about methane on space.com a week ago but it didn't cite anything specific. Yesterday, Dr, Grotzinger just replied with something like, "we don't have anything to report on that yet, Craig--stay tuned."

Yeah I remember that part too with Craig leaving the line then with a giggle. I think Dr. Grotzinger replied " ... we've got no statement on that yet Craig - stay tuned."

But still nice images comming down - sol 72 MR+ML:


There is another new one in the "drive drive drive" thread.

Note that feldspar is also an important component of basalt, so that's probably the most likely source rock, consistent with what the team says. Feldspar has a wide range of compositions (e.g., anorthosite feldspar is much poorer in sodium and richer in calcium than granite feldspar), and Curiosity can probably tell what kind of feldspar we have here- were any more specifics given at the briefing? Or are there any XRD experts out there who can read that diffraction pattern :-) ?

John

I hear you, John. I guess I ought to have stated my thought by saying I wonder if the source is plagioclase or alkali feldspar? The former is found both as laths within basalt (at least it is on Earth and on the Moon), and as purely anorthositic rock. Alkali feldspar is water-altered and is found (again, at least on Earth) in granitic rock.

However, as I noted in a response to Phil a while back, when you find plagioclase in basalt it is usually in the form of little, almost feathery intrusions in the basalt called laths. As I understand it, this is due to a plagioclase component in the lava melt which cannot mix with the pyroxene and/or olivine components of the lava, and it just solidifies in place in the same distribution found in the original melt, as the strings, strands and thin layers of the lighter, more aluminous plagioclase floated and were moved about as the original melt convected, moved and flowed. (I think of it as freezing a glass of water very quickly after trying to stir in a liquid that won't mix with the water; the non-miscible liquid will form flow structures within the water, which are then frozen into the ice.)

While these laths are not always highly identifiable in macroscopic images, they're usually fairly easily seen when you look with any reasonable magnification. I know I've looked for this kind of lath structure in the various basalts we've seen over the course of 36 years of Martian surface exploration, and I've not seen anything I can definitely say is a lath structure that would say for certain that Martian basalts have a significant feldspathic content.

I'm not saying it isn't there, I'm just saying that I've not seen it. Of course, it may be I wouldn't recognize a lath structure in situ -- I normally see it best in thin-section slides, after all. And, of course, I've not seen the basalt elemental abundance results of all of the MER sensors, at least not directly. So, I certainly can't be sure. I'd just be interested in seeing whether or not MSL finds a significant feldspathic component in the intact basalts it studies.

-the other Doug