Mars terrain analysis

Rizzamabob · 2007-05-23 03:16:31

Hey guys-girls,

A group of friends and I are currently learning about Mars and the different geology and
surface formations that occur on the planet. There are a number of unknown formations on the
attached image that we are having trouble describing.
- the blue "dust" looking particles to the east of the image
- the dark brown/black particles to the north of the image
We are also finding it hard to determine the different types of craters and old river/lake
formations. Can you please assist us in describing the formations on this image, the group
would greatly appreciate it.

Yours Sincerely,

Ryan, Tina and Jason

Rizzamabob · 2007-05-23 03:16:51

It wouldn't let me link to the photo in my first post, here it is

RobertDyck · 2007-05-23 20:51:16

Mineral identification requires spectra, not just a 3-colour image. However, blue usually indicates a copper compound. It could be copper sulphide (CuS), known by the mineral name Covellite.

Interesting: the blue streak follows a wind pattern, with concentrations in the "lee" of crater walls. This implies wind blowing from bottom to top with a blue mineral source off the bottom of the picture. If there is a source of blue mineral dust and it is covellite, that source would be a great place to mine copper. Is the source a volcanic fumarole?

The blue streaks follow what appear to be dried-up river channels. This is common with wind, the canyon walls channel wind. You can practically see the wind.

Dark brown in the upper-left is on the surface only, with light-brown at the bottom of valleys. It's also on the bottom of craters, but only in the centre. Hmm, does that indicate deposition of a light material or scouring of a dark layer off a light substrate? There are a few rocks indicate by a large light dot with a cone opening as a fan away from the rock. That indicates the action of wind, the rock obstructs wind. However the fans open toward the bottom-left, indicating wind flowed in the opposite direction than when the blue stuff was deposited. The bottom-left edge of dark stuff is ragged and craters have light stuff near their edge on both the up-wind and down-wind sides. That tells me the dark stuff is probably a thin layer that was scoured by wind, revealing light stuff underneath. Light stuff was also deposited by wind; notice craters have a wider band of light stuff at the upper-right crater wall. If that's where wind came from then that is deposition.

Blue stuff overlaps the dark stuff, so that indicates blue stuff is more recent. Also notice a greater concentration of blue in rough terrain, indicating it got stuck in cracks in the ground. That's another indicator it's wind deposited. Hmm, could this be a recently active fumarole?

Rizzamabob · 2007-05-23 21:53:00

Thanks for the great reply Robert,

Can you elaborate on the formation of craters, most seem to be quite old, since they are lacking ejecta. There is a crater in the bottom right corner that has a circle river valley/moat around what appears to be ejecta. We aren't quite sure how that was developed and why the valley runs around the ejecta in a circlish pattern. I'm assuming the broken pieces in the middle of the river/lake are rock formations which have been disturbed by wind.

Thanks

RobertDyck · 2007-05-23 22:20:48

The paper "A Global View of Martian Surface Compositions from MGS-TES" published in Science on 3 March 2000 included in its references a web address for a page. That web page had tables of minerals mentioned in the paper, the tables themselves were in a paper published in the Journal of Geophysical Research. I keep looking at this table as predominant minerals on Mars. It included 2 surface types:

Surface Type 1:
Microcline 5.8%
Andesine 22%
Bytownite 21.5%
Bronzite 5.4%
Augite1 12.4%
Augite3 11.3%
Serpentine 4.8%
Gypsum 1.8%
Calcite 3.7%
Dolomite 0.9%
Kaolinite 2.4%
Illite 9.9%

Surface Type 2:
Microcline 5.7%
Bytownite 27%
Actinolite 6.1%
Muscovite 5.7%
Bronzite 1.6%
Augite1 8.4%
Forsterite 2.9%
Gypsum 4.5%
Dolomite 3.3%
Fe-smectite 9.2%
Illite 2.2%
Obsidian Glass 22.8%

Fe-smectite is iron smectite, probably nontronite.

Notice 3 forms of clay, each indicating a different stage of hydrological weathering. Feldspar is igneous, it weathers into smectite, which weathers into illite, which weathers into kaolinite. Surface type 1 has high illite concentration relative to the other two forms of clay, and there is some kaolinite. Surface type 2 has high smectite with a little illite and no kaolinite. That indicates surface type 1 is more weathered than type 2.

Forsterite is a form of olivine, an igneous mineral that weathers quickly when exposed to water.

Microcline, bytownite, and andesine are forms of feldspar.

Actinolite and serpentine are hydrated magnesium silicate minerals; actinolite also has calcium. Crush either of these to form asbestos.

Augite is a mess, it's an igneous mineral that has a bit of everything. It has many forms depending on concentration of its ingredients. Notice the number after the name: 1 or 3. That indicates a form recorded in a thermal emission spectra catalogue.

These are the most common minerals on Mars. Look up their colour for light-brown, dark-brown, or black patches.

RobertDyck · 2007-05-23 23:10:33

There are frequent odd formations like this on Mars. Craters with clear crater walls and ejecta streaks, in the same terrain as sinuous river beds, wide patches that might be lakes, and evaporite plains. Mars has been changed by flowing water, meteorites, and wind. It gets even more messy when you see things like an extant glacial flow between two craters. This image doesn't have a glacier, but does have a sinuous river bed in the upper-left and wide flow beds on the right. The flat bottom tells me it was formed by water, not wind. The wide "lake" in the centre-right of the image has a couple flow channels connect to it. Be careful, wind that leaves streaks may flow backward to the water that formed the channels. Rough terrain in the "lake" looks like light material was transported away by wind. Probably it had a smooth bottom when water flowed. The fact narrow channels still have a smooth bottom but the "lake" as broken up tells me silt deposits in the channels was deeper than the lake. Or is that due to wind effects? The wide area to the bottom of the image has some roughness as well, but it's smaller bits. The bottom wide area looks like rocks left behind when flowing water scoured mud, while the central "lake" looks like mesas or buttes.

The "moat" formation in the bottom of the image is a strange one. It appears to be the left shore of the water feature. The centre is flat, smooth, and level with the surrounding terrain. It has blue streaks that appear to be recent deposits. The outline of the moat is roughly crater shaped, but the flat-smooth centre appears to have been formed along with the pre-water terrain. It's as if an old crater was filled in, then when a river flowed the water scoured the walls of the crater. Did flowing water dig form a ring that dug out a moat? That would require a fast moving river, something like the Niagara River. Or is that a wind feature? More likely water started it, then wind widened it. The form we see now follows the hardened walls of an ancient crater. Weird, huh?

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#1 2007-05-23 03:16:31

Re: Mars terrain analysis

#2 2007-05-23 03:16:51

Re: Mars terrain analysis

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Re: Mars terrain analysis

#4 2007-05-23 21:53:00

Re: Mars terrain analysis

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