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baric
2010-Jun-04, 11:57 PM
I understand that Mars is covered with iron oxides, but why is Mars unique in this respect?

There are other bodies, such as the Moon, which are not. Is there a hypothesis within the scientific community as to why Mars, in particular, ended up this way?

01101001
2010-Jun-05, 12:08 AM
Universe Today: Why is Mars Red? (http://www.universetoday.com/guide-to-space/mars/why-is-mars-red/)


Well, the short answer is that it isn't. For most of the planet, the red layer only covers a couple of millimeters and at its deepest, two meters.
The red color comes from various oxides of iron (hematite mostly) in very, very fine particles, and trace amounts of other elements including titanium, chlorine and sulfur.
One possible way the dust was created was by harder basalt rocks, which contain more feldspar, grinding against the softer basalt to create fine dust particles.
All of that iron had to come from somewhere: volcanoes. The best information that we have is that the surface of mars below the red layer is made up of hardened, low viscose lava: basalt. The concentration of iron in Mars' basalt is higher than that of Earth, which is why Earth is much less red.

baric
2010-Jun-05, 12:38 AM
The concentration of iron in Mars' basalt is higher than that of Earth, which is why Earth is much less red.

I understand this. Why does Mars, in particular, have a higher concentration of iron when compared to other bodies?

If it does not, then is this redness a predictable result of some Mars-specific characteristics: no magnetic field, no ocean or atmosphere?

alwaysnumb
2010-Jun-05, 01:25 AM
On earth the iron oxide gets disolved in water also the land gets covered with life and theres seas. But there are plenty of areas that its on the surface and the land is bright red.

01101001
2010-Jun-05, 03:31 AM
There's iron all over this system. Mars shows it off with color on its surface. Why its basalt might have somewhat more iron than Earth's I'm sure is just a matter of physical processes, original raw materials, energy, time, pressure, cycles, that create the basalt. Different chemistry occurs under different conditions. In the end though, I think Mars conditions mostly just make it look more vivid and apparent.

Universe Today: Why is Mars Red? New Study Offers Surprises (http://www.universetoday.com/2009/09/21/why-is-mars-red-new-study-offers-surprises/)


The scientists suspect that, as the quartz sand grains are tumbled around they get quickly eroded and an alteration of minerals through contact ensues. How exactly this happens need to be further investigated through more experimental and analytical work. What is clear though is that the first experiments show that this process occurs not only in air but also in a dried carbon dioxide atmosphere, that is, in conditions that perfectly resemble those occurring on Mars. It may also imply that the reddish Martian dust is geologically recent.

Oh, maybe here's the right detail you seem to be seeking: Cornell University: Athena Project: Fun Facts with Tommy Test Tubes (http://athena.cornell.edu/kids/tommy_tt_issue2.html)


The answer to the question of why Mars is red (and why there are dark areas on the Moon) is first because both worlds contain iron, like Earth contains iron. Secondly, the iron on the surface of Mars is more oxidized than the iron on the Moon, which is why Mars looks red and you see dark places on the Moon (remember, it's often called the "man on the Moon"). Why is iron on Mars more oxidized? Because it has an atmosphere that contains carbon dioxide (CO2) and water (H2O), both of which can be a source of oxygen for oxidizing iron. The Moon on the other hand, has a surface in a vacuum -- no atmosphere, no oxygen to make the iron red.

Google: "why is mars red" (http://www.google.com/search?client=safari&rls=en&q=%22why+is+mars+red%22)


About 109,000 results (0.14 seconds)

Enjoy.

01101001
2010-Jun-05, 03:43 AM
On earth the iron oxide gets disolved in water also the land gets covered with life and theres seas. But there are plenty of areas that its on the surface and the land is bright red.

US Department of Agriculture: Why are Georgia soils red? (http://www.ga.nrcs.usda.gov/technical/soils/red.html)


Not all Georgia soils are red, but many of them are. The State is well known for its abundance of "Georgia Red Clay". People often ask why the soils are red.

The red color that is so evident in Georgia soils is due primarily to iron oxides.

I've spent a lot of time on the Minnesota Iron Range. I expect soil to be red in some places. It's ordinary. It's irony! Minnesota Department of Natural Resources: The Universe Underfoot — September - October 2002 (http://www.dnr.state.mn.us/young_naturalists/soil/index.html)


Iron colors much of Minnesota’s soil. Just as oxygen reacts with iron and turns a nail rusty, iron in soil reacts with oxygen, creating shades of red and orange. To get yellows or browns, add organic matter.

baric
2010-Jun-05, 02:45 PM
Yes, I did try to read up on this a little before asking! I was not as interested in the source of the red, but the reason for the contrast with other terrestrial planets.

So really is just boils down to a simple function of atmospheric oxygen. Mars = red, Mercury&Moon = gray. Despite its oxygen, Earth is not red primarily because of its water oceans and ground cover from biotic processes. Does that sound correct? I guess Venus is also pretty red under that CO2 blanket.

Thanks again!

Sophic
2010-Jun-05, 06:38 PM
I don't think you'll find the answer you're looking for as one doesn't exist yet, nobody knows for sure how the iron oxide got there, there are different theories, water, volcanoes, meteorites, the atmosphere. I guess just pick which one you like best and go with it, until we know more about the planet.