New Bright Stuff, Paso Robles 2 Options

[slinted]

Another color shot of Arad in full filter came down today:

as well as some MIs
This stuff (which is looking very similar to the previous Paso Robles material) has got to be my favorite material we've seen from either rover, from a purely colorific standpoint.

[CosmicRocker]

It's just gorgeous, isn't it? I don't remember previous sightings being so colorful, but perhaps I have forgotten, or we didn't look as closely, earlier. Can anyone dig up some old images, or newly processed, old images?

I've been trying to imagine a sequence from the physical evidence here, and one which makes sense chemically from the color evidence. It's probably crazy to try, though. This soil is so churned up. I know we can't fully trust the colors, but the typical problems with the over-exposures on the blue end seem to be minor in these recent sets. It sometimes appears that these "full filter sets" are a bit better behaved.

I'm going to go _way_ out on a limb here and suggest that the yellow stuff is reminiscent of native sulfur, the shades of gray and exaggerated blue suggest reduced iron species in the particles, and the "rusty" orange-brown stuff resembles rock fragments containing oxidized iron ions. The white stuff has already been identified by SS as largely sulfates of iron.

Oh great. Apparently ferric sulfate can also be yellow. Nevermind...back to the drawingboard... Thank goodness someone will get the lowdown from the Moessbauer and APXS eventually.

[Bill Harris]

It _is_ hard to figure out exactly what is going on here. But I think that your drawing board is still good, think of sulfates in various states of oxidation-reduction with different metals balancing out the SO4's. I've seen/heard of that happening in minespoil piles with pyrite oxidizing like mad til it sucks up all the O2, then it switches gears. Sulfates are important since they serve as an energy source for a class of microbes, the thiobacillus group. Ya gotta have food for bugs in the desert...

Still digging in my archives for colorful images. I _do_ need some sort of indexing system.

--Bill

[sattrackpro]

It _is_ hard to figure out exactly what is going on here.

Sure is... I'm not much of a chemist, or geologist, just an avid rock-hound that's been tinkering at the hobby for about 50 years... I've seen stuff like this right here on good old terra firma quite often, and your comment on minespoil nails exactly where I've seen stuff like this.

Typical content is just SiO2, and CaCO3, but the ‘pretty stuff’ is in metal oxides, primarily iron, aluminum, magnesium and lead - in that order of prominence. The zeolites and feldspars being what I’m after (crystalline forms of) - and this mars dig looks akin to Analcime - often a multicolored zeolite, but usually white. It's usually aluminum based, but with lead it goes multi-color. Wish they would publish more on what elements the spectrographic work shows...

[Mongo]

Wish they would publish more on what elements the spectrographic work shows... 

slinted gave a link to a paper that goes into great detail on the results of 93 different APXS integrations, on the first page of this thread.

Examples of several results from that paper (numbers in parenthesis are two-sigma errors):

sol 14 Gusev soil (integration time 13.5 hours)

Na2O: 2.8 % (0.3 %)
MgO: 8.34 % (0.12 %)
Al2O3: 9.89 % (0.14 %)
SiO2: 46.3 % (0.5 %)
P2O5: 0.87 % (0.08 %)
SO3: 6.61 % (0.08 %)
Cl: 0.78 % (0.02 %)
K2O: 0.48 % (0.06 %)
CaO: 6.36 % (0.05 %)
TiO2: 0.86 % (0.07 %)
Cr2O3: 0.31 % (0.03 %)
MnO: 0.33 % (0.01 %)
FeO: 16.0 % (0.11 %)
Ni: 556 ppm (51 ppm)
Zn: 293 ppm (18 ppm)
Br: 31 ppm (17 ppm)

sol 172 Pot of Gold RAT (integration time 5.0 hours)

Na2O: 3.0 % (0.2 %)
MgO: 9.91 % (0.13 %)
Al2O3: 10.32 % (0.13 %)
SiO2: 42.9 % (1.4 %)
P2O5: 1.08 % (0.08 %)
SO3: 7.96 % (0.10 %)
Cl: 0.57 % (0.01 %)
K2O: 0.20 % (0.06 %)
CaO: 5.86 % (0.05 %)
TiO2: 0.77 % (0.07 %)
Cr2O3: 0.27 % (0.03 %)
MnO: 0.24 % (0.01 %)
FeO: 16.7 % (0.12 %)
Ni: 894 ppm (52 ppm)
Zn: 112 ppm (13 ppm)
Br: 77 ppm (17 ppm)

sol 401 PasoRobles disturbed soil (integration time 2.7 hours):

Na2O: 1.6 % (0.2 %)
MgO: 5.53 % (0.09 %)
Al2O3: 4.13 % (0.07 %)
SiO2: 21.8 % (0.3 %)
P2O5: 5.61 % (0.14 %)
SO3: 31.7 % (0.30 %)
Cl: 0.55 % (0.02 %)
K2O: 0.19 % (0.06 %)
CaO: 6.84 % (0.06 %)
TiO2: 0.62 % (0.07 %)
Cr2O3: 0.04 % (0.03 %)
MnO: 0.25 % (0.01 %)
FeO: 21.0 % (0.12 %)
Ni: 109 ppm (49 ppm)
Zn: 98 ppm (18 ppm)
Br: 494 ppm (26 ppm)

Bill

[dilo]

Hey, Spirit is working on this stuff also after "local Sunset"!
(Sol 723, enhanced brightness, crossed eyes)

Attached thumbnail(s)

 

[JonClarke]

This stuff (which is looking very similar to the previous Paso Robles material) has got to be my favorite material we've seen from either rover, from a purely colorific standpoint.

Jarosite, which is yellow, has to be a strong candiate. Alunite and Ca-Mg-NA sulphates are all white. Given the amount of jarsoite that is supposed to exist on Mars it is nice to actually see some at last.

Jon

[Bill Harris]

That's right: color. Mineralogy 101. Duh.

--Bill

[CosmicRocker]

Hey, Spirit is working on this stuff also after "local Sunset"! 
(Sol 723, enhanced brightness, crossed eyes)

Hehe , she is quite a workaholic, isn't she?

The appearances of such stuff are among the most interesting observations Spirit has returned from Gusev Crater.

[Nix]

true color is up;

http://marswatch.astro.cornell.edu/pancam_...true_color.html

Nico

[jaredGalen]

Wow, Spirit does look really dusty in this one;
http://marswatch.astro.cornell.edu/pancam_..._1_True_RAD.jpg

[dot.dk]

Wow, Spirit does look really dusty in this one;
http://marswatch.astro.cornell.edu/pancam_..._1_True_RAD.jpg

I have noticed how the solar panels have lost some of its great dark color in the last few months...

I think being down here in the basin deposits more dust than if you are on a hill

[sattrackpro]

slinted gave a link to a paper that goes into great detail on the results of 93 different APXS integrations, on the first page of this thread.
- - -
Bill

Thanks very much, Bill - that is a great piece - very informative! There are also a number of other pdf's in that pip directory (see just by trimming the trailing file) that are most interesting.

[Jeff7]

I have noticed how the solar panels have lost some of its great dark color in the last few months...

I think being down here in the basin deposits more dust than if you are on a hill 

Being near El Dorado probably doesn't help any - looks like a prime spot for dust deposition.

[Toma B]

Wow, Spirit does look really dusty in this one;
http://marswatch.astro.cornell.edu/pancam_..._1_True_RAD.jpg

WOW that's awfully dirty!?! When did that hapen???
Get out of there Spirit, fast!!!