Research says Mars had oxygen-rich atmosphere 4000 million years ago

Jun 19, 2013
Mars
Mars, photographed by the Viking Orbiters in the 1970s. Credit: NASA

Differences between Martian meteorites and rocks examined by a NASA rover can be explained if Mars had an oxygen-rich atmosphere 4000 million years ago—well before the rise of atmospheric oxygen on Earth 2500 million years ago.

Scientists from Oxford University investigated the compositions of found on Earth and data from NASA's 'Spirit' rover that examined surface rocks in the Gusev crater on . The fact that the surface rocks are five times richer in nickel than the meteorites was puzzling and had cast doubt on whether the meteorites are typical volcanic products of the red planet.

'What we have shown is that both meteorites and surface volcanic rocks are consistent with similar origins in the deep interior of Mars but that the surface rocks come from a more oxygen-rich environment, probably caused by recycling of oxygen-rich materials into the interior,' said Professor Bernard Wood, of Oxford University's Department of , who led the research reported in this week's Nature.

'This result is surprising because while the meteorites are geologically 'young', around 180 million to 1400 million years old, the was analysing a very old part of Mars, more than 3700 million years old.'

Whilst it is possible that the geological composition of Mars varies immensely from region to region the researchers believe that it is more likely that the differences arise through a process known as subduction – in which material is recycled into the interior. They suggest that the was oxidised very early in the history of the planet and that, through subduction, this oxygen-rich material was drawn into the shallow interior and recycled back to the surface during eruptions 4000 million years ago. The meteorites, by contrast, are much younger that emerged from deeper within the planet and so were less influenced by this process.

Professor Wood said: 'The implication is that Mars had an oxygen-rich atmosphere at a time, about 4000 million years ago, well before the rise of on earth around 2500 million years ago. As oxidation is what gives Mars its distinctive colour it is likely that the 'red planet' was wet, warm and rusty billions of years before Earth's atmosphere became oxygen rich.'

Explore further: India's spacecraft 'on target' to reach Mars

More information: Volcanism on Mars controlled by early oxidation of the upper mantle, dx.doi.org/10.1038/nature12225

Related Stories

Martian rock from Sahara desert unlike others

Jan 03, 2013

Scientists are abuzz about a coal-colored rock from Mars that landed in the Sahara desert: A yearlong analysis revealed it's quite different from other Martian meteorites. Not only is it older than most, ...

Extensive water in Mars' interior

Jun 21, 2012

Until now, Earth was the only planet known to have vast reservoirs of water in its interior. Scientists analyzed the water content of two Martian meteorites originating from inside the Red Planet. They found ...

Studying meteorites may reveal Mars' secrets of life

May 01, 2013

In an effort to determine if conditions were ever right on Mars to sustain life, a team of scientists, including a Michigan State University professor, has examined a meteorite that formed on the red planet ...

First meteorite linked to Martian crust

Jan 03, 2013

After extensive analyses by a team of scientists led by Carl Agee at the University of New Mexico, researchers have identified a new class of Martian meteorite that likely originated from the Mars's crust. ...

Moroccan desert meteorite delivers Martian secrets

Oct 11, 2012

(Phys.org)—A meteorite that landed in the Moroccan desert 14 months ago is providing more information about Mars, the planet where it originated. University of Alberta researcher Chris Herd helped in the ...

Meteorites reveal warm water existed on Mars

Nov 15, 2012

New research by the University of Leicester and The Open University into evidence of water on Mars, sufficiently warm enough to support life, has been published this week in the journal Earth and Planetary Sc ...

Recommended for you

India's spacecraft 'on target' to reach Mars

20 hours ago

An Indian spacecraft is on course to reach Mars, an official said Monday, following a 666-million-kilometre voyage that could see New Delhi's low-cost space programme win Asia's race to the Red Planet.

Rosetta's lander Philae will target Site J

22 hours ago

(Phys.org) —Rosetta's lander Philae will target Site J, an intriguing region on Comet 67P/Churyumov–Gerasimenko that offers unique scientific potential, with hints of activity nearby, and minimum risk ...

User comments : 18

Adjust slider to filter visible comments by rank

Display comments: newest first

dopeSlice
2.7 / 5 (7) Jun 19, 2013
wtf! 4000 million. That must be a type-o. Do you mean 400 million or 4 billion?
drel
4.3 / 5 (4) Jun 19, 2013
I understand that earths oxygen rich atmosphere developed as a result of photosynthesis. Is there some other natural process (other than photosynthesis) that can explain an oxygen rich atmosphere in Mars' ancient past?
Q-Star
2.5 / 5 (8) Jun 19, 2013
4 billions. Ya have to be careful when a Brit is dealing with millions/billions. But, yeah, they are talking about a very young Mars. In the original article in Nature, they report < 3.8 billion.
Q-Star
3.2 / 5 (11) Jun 19, 2013
I understand that earths oxygen rich atmosphere developed as a result of photosynthesis. Is there some other natural process (other than photosynthesis) that can explain an oxygen rich atmosphere in Mars' ancient past?


The mechanism they discuss in their study is the release of O from FeO, MgO and a couple of other compounds that I can't remember now. The entire Nature article might be available on-line. (Or maybe not, they prefer to sell ya the most recent articles.)

By the By: Oxygen is the most abundant element in the Earth, by a huge margin. Third most abundant element in the universe as a whole.
Torbjorn_Larsson_OM
4.7 / 5 (6) Jun 19, 2013
This is not necessarily the bad news for early Mars habitability it at first blush looks as, as oxygen quenches organic production and destroys organics.

Oxygen liberation would have been a gradual process, and if sufficiently complex cells had arose early they could, as they did here much later, eventually evolve to handle the poison.

Even if not, our own early life were homologous to alkaline hydrothermal vent chemistry in their metabolism, and such environments when situated in deep seas can be low in oxygen. Some predictions make an early northern Mars ocean with hundreds of meters of water depth.

All in all it is too early to tell if this is a stumble block for a martian biosphere.

Re the CHNOPS elements, chances are our cells use of them is precisely because they are so common. (With carbon the exception, since it is pretty much necessary for its chemical flexibility. Luckily it _is_ common.)
MR166
1 / 5 (5) Jun 19, 2013
"Scientists from Oxford University investigated the compositions of Martian meteorites found on Earth"

OK please help me out here. How can anyone tell where a meteorite found on Earth came from?
Q-Star
2.5 / 5 (8) Jun 19, 2013
"Scientists from Oxford University investigated the compositions of Martian meteorites found on Earth"

OK please help me out here. How can anyone tell where a meteorite found on Earth came from?


The short answer is the chemical make up and the isotopes of those elements. The long answer would take many pages.
Shootist
1.4 / 5 (16) Jun 19, 2013
wtf! 4000 million. That must be a type-o. Do you mean 400 million or 4 billion?


Look up numeric nomenclature. Google is your friend.

And no, it is not a typo just your lack of understanding of the world around you.
down
1 / 5 (6) Jun 19, 2013
This makes me wonder if we are looking at Earth's future when we look at Mars.
grondilu
5 / 5 (1) Jun 20, 2013
By the By: Oxygen is the most abundant element in the Earth, by a huge margin. Third most abundant element in the universe as a whole.


Sure, but isn't it also very reactive, so that it's normally not present in its molecular form (O2 or O3)?

I'm no expert but I thought that an oxygen-rich atmosphere was a very strong indicator for photosynthesis. If it is confirmed that mars's atmosphere was once rich in oxygen, that would have to mean that it's not such a good indicator for life after all.
Sinister1811
2.3 / 5 (6) Jun 20, 2013
Well, if the rovers find fossil bacteria on Mars eventually, this would prove the biological origin of Oxygen in Mars's atmosphere. Until then, all we can guess is that it had chemical or geological origins (any ideas?).
Egleton
3 / 5 (6) Jun 20, 2013
Professor James Lovelock said that if you want to identify if a planet is alive, check the spectrum for oxygen.
It is too reactive to exist in a free state for long. If it is present at say 22.3%, then it is being held at that value by the feedbacl loops created by life.
Oxygen without life is like a bicycle without a rider. It is unstable.
Torbjorn_Larsson_OM
5 / 5 (3) Jun 20, 2013
@down: Not really our future.

This is the consensus as of now, as you can find in reviews:

As the Sun heats up during its aging in the star main sequence, our hotter climate will mean higher erosion and sedimentary rates. This will soak up the carbon dioxide into sediments, eventually making plants and so oxygen-dependent animals and fungi extinct.

That will happen within 0.2 - 1.5 billion years. (I doubt the bounds have improved much since I last looked at this.) After that, life will survive in refugia until 2.5 - 3.5 billion years in the future. Likely deep caves will see archaeal life surviving on meager energy resources, they were first clear division of life and they will be the last.

Some 4.5 - 5.5 billion years from now, the Sun will either swallow Earth in its read giant dying phase, or bake it on an extended orbit caused by tidal forces as the swollen star surface gets closer.

And that's it.
Torbjorn_Larsson_OM
5 / 5 (3) Jun 20, 2013
@grondilu: A stable oxygen atmosphere is and remains a great indicator of life on mature planets. In our case, oxygenating photosynthesis took ~ 2 billion years to evolve and oxygenate the atmosphere against the reduction of iron. (The Great Oxygenation Event ~ 2.5 billion years ago.)

The high oxygen fugacity that these mineral results tells of wasn't permanent, oxygen was liberated by volcanism and when it went the oxygen recycling disappeared.

@Sinister1811: I don't understand. This article tells us that oxygen was liberated by geological processes, not biological. There is no "Oxygen in Mars's atmosphere" to be found today (except which is liberated by UV photolysis of water).

Even if we would find evidence for earlier life, these results would preclude us from tying any observed early oxygen to life. In that sense, it made astrobiology of Mars harder.
Sinister1811
2.3 / 5 (6) Jun 20, 2013
@Torbjorn Larsson Sorry, I wasn't very clear with that comment. I meant the fact that there was an oxygen atmosphere early in Mars's history (obviously there's no oxygen there now!). And you are right, it does say that it was due to geological processes in the article. My apologies. I must've skipped over that part. Cheers.
Anda
2.3 / 5 (3) Jun 20, 2013
Their explanation doesn't make sense. Where does this oxygen came from?
In earth we needed 2000 My and the origin was life and there's no evidence this life existed in the first 500My on earth.
How did Mars obtain this oxygen in the first 500 My of existence of the planet?
If you want to use such an explanation better argument it with data explaining the causes. Those "geological" processes.
nkalanaga
5 / 5 (1) Jun 20, 2013
Anda: Mars may have cooled faster than Earth, being smaller, so its surface could have been suitable for life earlier. Also, being further out, it probably received more organic compounds from asteroids and comets than Earth. Finally, collision speeds were probably lower, because Mars has less gravity than Earth, and because objects move slower further from the Sun, so the organics had a better chance of surviving impact.

I won't say Mars DID have life that far back, but it could have had a head start.
antialias_physorg
3 / 5 (2) Jun 24, 2013
I'm no expert but I thought that an oxygen-rich atmosphere was a very strong indicator for photosynthesis.

Given a good energy source there are plenty of mechanisms that put oxygen in an atmosphere besides photosynthesis. E.g. an atmophere with very strong lightning activity would do the trick. Vulcanism can play a role. Heck, you could probably find a reaction that depends solely on intense solar radiation to liberate oxygen from some abundantly available compound.