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Solon
2012-Oct-26, 06:14 PM
If anyone has more questions on this topic, do not hesitate to ask....

I am wondering about the origin of the surface iron on Mars. All the iron should have settled to the core, but the surface 'sand' is rich in iron, and then there are the huge number of Blueberries. Could volcanoes have brought some up from great depth, or is it most likely from iron rich impactors? And if so, how does it get formed into the spheres? Thanks.

Jeff Root
2012-Oct-26, 08:05 PM
I never learned how the "blueberries" formed or what they
are composed of, but the iron oxides in the regolith isn't
mysterious. Being smaller than Earth, with lower gravity,
the iron would have less reason to sink than it does on
Earth. And Earth still has significant amounts of iron near
the surface. Look at true-color images of Earth's deserts.
they are about the same color as Mars, for the same reason.
A small percentage of the surface material is iron oxides,
which is all it takes to make it orange. On Mars, the fine
dust shows up as orange while the coarser grit and rock is
darker. The dust gets piled up in separate areas by wind,
so it doesn't cover the whole surface. On Earth, a lot of
other things are going on to bury or hide the iron oxides,
including water, water erosion, plants, and organic soil.

The southwestern USA, the Sahara in northern Africa, and
most of the interior of Australia are all orange because
there is nothing there to hide the iron oxides.

-- Jeff, in Minneapolis

IreneAnt
2012-Oct-26, 09:55 PM
Hi Solon,

I split this off to a separate thread, because it is far more specific than the topic of the original thread.

Your question is actually quite complex. Let me see if I can address it...

Ultimately all planets are made by accretion from the building blocks of the solar system. However, this process dominates early on, so iron brought by impactors would be involved in the planetary differentiation process. During differentiation, a lot (but not all) of the iron is removed to the core. Still, enough remains in the mantle and crust to make iron rich minerals. Volcanism then takes these iron rich minerals and preferentially brings them from the mantle to the surface, in the form of basalts. So, any planet where basalt volcanism occurred is expected to have iron at the surface.

The reason why we notice the iron on Mars so much is because of it's colour. Studies show that the iron on Mars is rusted, giving it it's noticeable red colour. The rustiness of martian iron is often used as evidence for the presence of water early in Mars' history. It is thought that oxygen and iron dissolved in the water, where they combined to form rust, which then precipitated to the bottom of martian lakes and oceans. This process also occurred on Earth around 2 b.y. ago, creating massive Banded Iron Formations. The difference on Mars was that the water evaporated (and escaped into space), leaving a dry rusty soil behind (much like many dry desert regions on Earth).

The iron spherules (commonly called blueberries) discovered recently on Mars are thought to be concretions of the rust mineral hematite. Individual hematite grains are thought to have been rolled by waves along the bottom of martian lakes and oceans. As they rolled, more hematite layers would have been deposited on their surfaces creating the round shape. Concretions are also found on Earth, composed most commonly of calcite, silica, or hematite (Wikipedia has a decent article about these (http://en.wikipedia.org/wiki/Concretions) if you are interested).

I hope this helps.

IreneAnt
2012-Oct-26, 09:59 PM
And thanks to Jeff Root for slipping in a very good answer as I was pulled away to do 10 different other things while trying to post my response. :)

Jeff Root
2012-Oct-27, 02:34 AM
I thought the "blueberries" might be hematite, but I didn't
remember that, and I wasn't sure the necessary instruments
were available on the rovers which discovered the blueberries
to determine their composition with any certainty. I have a
small piece of what I am pretty sure is hematite sitting on
my bookshelf right behind me. Very dark gray with just a
tinge of rusty-ruddiness in one area. From the iron mine
in northern Minnesota where the neutrino detector is.

-- Jeff, in Minneapolis

Solon
2012-Oct-27, 08:51 PM
Thanks for the info IreneAnt, but having had a look at a few proposed mechanisms I still do not see a coherent, comprehensive or verifiable model. So at the risk of being placed in the ATM or Conspiracy threads, I am wondering if I might ask, and who would be best to ask, about the possibility of the Martian surface features (and by inference, other planetary surfaces) being the result of processes such as heavy ion bombardment, ion acoustic waves, aggregation, dis-aggregation, shattering by pulsed electric fields, and, based on the known electrical and mechanical properties of particular rocks, processes that rely on the piezoelectric (and obverse), dielectric, resistance, reluctance, etc. variables. This scenario would be based on the concept of CMEs at magnitudes far greater than we presently experience, particularly with respect to the iron ion density. So I guess my bottom line would be, is it possible for such mechanisms to explain the presently unexplained?

astrostu
2012-Oct-28, 06:15 PM
Yeah, you're getting pretty close to ATM stuff with your post. As with all things, the onus is on the person making the more "out there" claim to show that it is at least as likely as the generally accepted model (from a basic physics, observation, etc. standpoint), has evidence to back it up, and it can explain the evidence used to support the accepted models at least as well if not better than the accepted models.

Githyanki
2012-Oct-31, 06:53 PM
While we're talking about iron-oxide on Mars, could it have similar origins as it did on Earth, 2BYA, from microbes converting CO2 into oxygen?

IreneAnt
2012-Nov-01, 03:53 PM
While we're talking about iron-oxide on Mars, could it have similar origins as it did on Earth, 2BYA, from microbes converting CO2 into oxygen?

Theoretically yes, if (and that's a big if) there were/are microbes on Mars. However, microbes aren't strictly necessary for iron oxides to form. Only oxygen is necessary, and it doesn't matter how that oxygen is made. So, there is no way to prove that the oxygen used to create iron oxides comes specifically from microbes. On Earth, the microbes are invoked because we have fossil evidence that they existed during the time when large quantities of iron oxides (called Banded Iron Formations) were being deposited. At present, we have no such evidence for Mars, so it is more logical to assume the oxygen involved in iron oxide formation comes from non-living sources.

Solon
2012-Nov-01, 07:01 PM
"If you look at the soil composition of Mars, the one thing that really strikes you is that it's 5 to 14 percent iron oxide," said Dr. Peter Curreri, a materials scientist at NASA's Marshall Space Flight Center. "It's almost ore-grade material."
http://science.nasa.gov/science-news/science-at-nasa/1999/msad03mar99_1/

I looked at the Apollo Moon surface samples, and iron oxide levels were between 10 and 20%.
http://www.permanent.com/lunar-geology-minerals.html
I don't think anyone is suggesting flowing water on the Moon, or microbes.

Only oxygen is necessary, and it doesn't matter how that oxygen is made.
A CME carries oxygen.

cjameshuff
2012-Nov-01, 07:59 PM
Thanks for the info IreneAnt, but having had a look at a few proposed mechanisms I still do not see a coherent, comprehensive or verifiable model.

Mechanism for what? You seem to be expecting that differentiation would separate every trace of iron into the core. Why? What mechanism would you propose for such complete differentiation?



So at the risk of being placed in the ATM or Conspiracy threads, I am wondering if I might ask, and who would be best to ask, about the possibility of the Martian surface features (and by inference, other planetary surfaces) being the result of processes such as heavy ion bombardment, ion acoustic waves, aggregation, dis-aggregation, shattering by pulsed electric fields, and, based on the known electrical and mechanical properties of particular rocks, processes that rely on the piezoelectric (and obverse), dielectric, resistance, reluctance, etc. variables. This scenario would be based on the concept of CMEs at magnitudes far greater than we presently experience, particularly with respect to the iron ion density. So I guess my bottom line would be, is it possible for such mechanisms to explain the presently unexplained?

Why would you ever propose such an excessively complex scenario for something so little in need of explanation?



I don't think anyone is suggesting flowing water on the Moon, or microbes.

Because the iron oxide common on the moon is FeO, which does not indicate the presence of water. Mars is colored red with Fe2O3 and FeO(OH).



A CME carries oxygen.

So what? Oxygen is the most abundant element in the universe apart from hydrogen and helium. Terrestrial planets are essentially balls of iron, oxygen, and silicon with small amounts of other elements.

Icefox
2012-Nov-01, 08:39 PM
The reason Mars has iron on the surface is exactly the same as why Earth has iron on the surface.

When a planet forms, most of the iron sinks to the core, and some of it is chemically bound in minerals in the mantle. So, the mantle of the planet has iron-containing minerals in it. These minerals partially melt to form magma, and some of the iron atoms go into the melt, and that magma erupts onto the surface of the planet. So, iron ends up on the planet's surface. Most of this magma forms a rock called basalt, which is quite similar in composition both on Earth and Mars, since it comes from similar source material (the bulk chemistry of Earth and Mars is not very different). We have samples of Martian basalts from meteorites, and they are generally similar to Earth basalts, which also tend to have high amounts of iron (5-20%). We know from orbital images that most of Mars is covered with basalt, and materials derived from basalt like dust and sand... But most of Earth is covered with basalt as well, or has been at one time or another.

Here's some pictures of Earth basalts:
http://tinyurl.com/bkxjyus
http://www.columbiariverimages.com/Images/oak_point_weathered_basalt_2003.jpg
http://skywalker.cochise.edu/wellerr/rocks/igrx/6maui-red-oxidatin426.jpg
http://www.qub.ac.uk/geomaterials/weathering/causeway/images/photoText/geologic_succession2.JPG
http://tinyurl.com/a2gek87

Looks pretty iron-rich to me.

IreneAnt
2012-Nov-02, 02:41 AM
http://science.nasa.gov/science-news/science-at-nasa/1999/msad03mar99_1/
I looked at the Apollo Moon surface samples, and iron oxide levels were between 10 and 20%.
http://www.permanent.com/lunar-geology-minerals.html
I don't think anyone is suggesting flowing water on the Moon, or microbes.


Because the iron oxide common on the moon is FeO, which does not indicate the presence of water. Mars is colored red with Fe2O3 and FeO(OH).

Very well said, cjameshuff. I was just about to reply to Solon, when I saw your excellent response.

Solon
2012-Nov-03, 07:35 PM
@cjameshuff

Mechanism for what? You seem to be expecting that differentiation would separate every trace of iron into the core. Why? What mechanism would you propose for such complete differentiation?

I haven't found any hard and fast figures for the degree of differentiation, as it seems there are many variables that affect the process. 20% in the crust just sounded high to me.


Why would you ever propose such an excessively complex scenario for something so little in need of explanation?

Glad I didn't throw in ion etching and sputtering too! If a CME was to be powerful enough then the mechanisms to produce the planetary surfce materials and features are known and accepted science, there is no doubt there. The question of if a CME could ever be of the reqired magnitude is the tough one to answer, due to lack of succesful models in explaining the CME mechanism. However, the only answer I can obtain from an expert is from the NRL, and their model does not put an upper limit on the magnitude of the magnetic energy injected into the quiescent solar "flux ropes".
Mr Chen has a PPT presentation on CMEs, though there is no discussion of 'magnitude'.
http://www.pppl.gov/colloquia_pres/WC20APR2011_JChen.ppt
And before you go saying I am advocating for an ATM idea, I am not, I am inquiring into the scientific possibility, and the name "CosmoQuest" would seem to indicate a place to question and learn about the cosmos, though my own and others experiences would seem to suggest, unfortunately, exactly the opposite. Hmm...Maybe I'm suggesting a Conspiracy here??

publiusr
2012-Nov-10, 06:49 PM
All that iron rust going to waste on the surface. If only I could clean that up and have metal from it.

Solon
2012-Nov-15, 06:49 PM
I suppose it is unreasonable to expect an opinion from the experts about the maximum possible CME events our Sun could produce if the models have no upper limits on the magnetic energy injection to the flux tubes, but other Sun-like stars have been observed to produce much larger events.

From wiki:

As of 2000, nine superflare stars have been found, some of them similar to our Sun.[1] The energy released during such a flare is 100 times to 10 million times that of the sun's largest coronal mass ejections.

But:


Superflares increase the brightness of the star by up to 20 times its normal brightness and the luminosity by 1,000 times. They may last from a few hours to a week. If the Sun were to release a superflare, it would make a winter day as warm as a summer day.

I'd have thought there would be a much larger effect than that, but have no idea how they come to such a conclusion. That would put the kibosh on the idea of planet/moon surface modification by flare/CME though.
More recent studies from Kepler raise questions about how slow rotating Suns can produce such high energy events.

'Superflares' erupt on some Sun-like stars.

The flares on our Sun are thousands of times punier than those on similar stars, Kepler observations suggest.

http://www.nature.com/news/superflares-erupt-on-some-sun-like-stars-1.10653

IreneAnt
2012-Nov-20, 07:07 PM
I suppose it is unreasonable to expect an opinion from the experts about the maximum possible CME events our Sun could produce if the models have no upper limits on the magnetic energy injection to the flux tubes, but other Sun-like stars have been observed to produce much larger events.


Hi Solon,

I confess that it is unrealistic to expect a response regarding CME events (a topic relating to solar astrophysics) from the kinds of experts who hang out in the Geology and Planetary Surfaces thread. I am sorry that I personally didn't respond to your comment, but seeing as I have no expertise in CME's, I kept quiet. I suspect you didn't get an answer here from an actual astrophysicist because they just don't monitor these threads (there's too much stuff on this forum for any expert to monitor all of it). This does mean that when you have questions that span disciplines like this, you may have to cross post on several forums. Or look up the information the way you did and answer you own question (very well done there, by the way).

I hope this helps in some small way.

Solon
2012-Nov-23, 10:13 PM
Hi IreneAnt, thanks for the reply.

Or look up the information the way you did and answer you own question.
Yes, but are the conclusions I might reach scientifically reasonable? I have looked at some material that leads me to be believe it is naive of us to say our Sun has never mega-flared, as it seems to be part of the process of accretion. That older stars also flare is accepted, but due to a different process, a close-in hot Jupiter class object being a contender. Given the accepted age of our Sun, I'd think such events must have occurred, and most likely a number of times.
Flaring Young Stars
http://www.cfa.harvard.edu/news/2010/su201001.html
In looking at some of the mineral maps of the Moon and Mars, I think I see distributions whos shapes look more like sputtering, thin film deposition, and other processes in keeping with those a mega-flare/CME event could produce. The well defined layering of Lunar hills observed by the Apollo astronauts is explained by the accumulation of material that was ejected by impactors, but I don't think any close up examination of the layered hills was ever performed, so if it was a loose or compacted or fused material is unknown. The pits also show distinct layering, but again, without hands-on examination, we can only guess at the composition.
17722
Specie separation in a bulk plasma flow might account for the layering?
And I know we are way off topic now, but the possibility that external rather than internal energies are involved on all the Solar system bodies, including the Earth, may explain features such as the Deccan or Siberian Traps, for which no magma sources have been identified, and which would require numerous simultaneous sources, along with an explanation of the heat origin. I don't think I'm ready to propose ATM yet, more research needed, but I don't believe the idea immediately dismissible.

IreneAnt
2012-Dec-02, 04:46 AM
Hi Solon,

The layering in the picture you show is in fact believed to be the result of multiple basalt flows, exactly like the Deccan or Siberian Traps. That is what the maria are believed to most closely resemble. So, for these layers, no solar mega flares are required.

I'm not quite sure which "layered hills" you are referring to, but the Apollo missions did return soil cores that were extensively studied. The soils were found to be generally compacted beyond a few centimeters depth. In some cases, distinct impact ejecta layers could be seen. So again, no mega flares needed.

As to the mineral distributions resembling sputtering, I am not sure what shapes are you talking about. There are lots of different mineral distributions, with many different reasons for their shapes, so can't really go into that without more details.

I hope that helps somewhat.