Water on ancient Mars

Analysis of a Martian meteorite reveals evidence of water 4.4 billion years ago


Research News


There’s a long-standing question in planetary science about the origin of water on Earth, Mars and other large bodies such as the moon. One hypothesis says that it came from asteroids and comets post-formation. But some planetary researchers think that water might just be one of many substances that occur naturally during the formation of planets. A new analysis of an ancient Martian meteorite adds support for this second hypothesis.

Several years ago, a pair of dark meteorites were discovered in the Sahara Desert. They were dubbed NWA 7034 and NWA 7533, where NWA stands for North West Africa and the number is the order in which meteorites are officially approved by the Meteoritical Society, an international planetary science organization. Analysis showed these meteorites are new types of Martian meteorites and are mixtures of different rock fragments.

The earliest fragments formed on Mars 4.4 billion years ago, making them the oldest known Martian meteorites. Rocks like this are rare and can fetch up to $10,000 per gram. But recently 50 grams of NWA 7533 was acquired for analysis by the international team in which Professor Takashi Mikouchi at the University of Tokyo was participating.

“I study minerals in Martian meteorites to understand how Mars formed and its crust and mantle evolved. This is the first time I have investigated this particular meteorite, nicknamed Black Beauty for its dark color,” said Mikouchi. “Our samples of NWA 7533 were subjected to four different kinds of spectroscopic analysis, ways of detecting chemical fingerprints. The results led our team to draw some exciting conclusions.”

It’s well known to planetary scientists that there has been water on Mars for at least 3.7 billion years. But from the mineral composition of the meteorite, Mikouchi and his team deduced it’s likely there was water present much earlier, at around 4.4 billion years ago.

“Igneous clasts, or fragmented rock, in the meteorite are formed from magma and are commonly caused by impacts and oxidation,” said Mikouchi. “This oxidation could have occurred if there was water present on or in the Martian crust 4.4 billion years ago during an impact that melted part of the crust. Our analysis also suggests such an impact would have released a lot of hydrogen, which would have contributed to planetary warming at a time when Mars already had a thick insulating atmosphere of carbon dioxide.”

If there was water on Mars earlier than thought, that suggests water is possibly a natural byproduct of some process early on in planet formation. This finding could help researchers answer the question of where water comes from, which in turn could impact theories on the origins of life and the exploration for life beyond Earth.


Journal article

Zhengbin Deng, Frédéric Moynier, Johan Villeneuve, Ninna K. Jensen, Deze Liu, Pierre Cartigny, Takashi Mikouchi, Julien Siebert, Arnaud Agranier, Marc Chaussidon, Martin Bizzarro. Early oxidation of the martian crust triggered by impacts. Science Advances. DOI: 10.1126/sciadv.abc4941

Funding information

F.M. acknowledges the ERC under the H2020 framework programme/ERC grant agreement no. 637503 (Pristine). M.C. and F.M. thank financial support from the UnivEarthS Labex programme at Sorbonne Paris Cité (ANR-10- LABX-0023 and ANR-11-IDEX-0005-02), the ANR CRADLE project (ANR-15-CE31-0004-1), the IPGP platform PARI, and the Region Île-de-France Sesame grant no. 12015908. M.B. acknowledges funding from the Carlsberg Foundation (CF18_1105), the Danish National Research Foundation (DNRF97), and the European Research Council (ERC Advanced Grant Agreement 833275-DEEPTIME).

The University Museum at The University of Tokyo – http://www.um.u-tokyo.ac.jp/index_en.html

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October 31, 2020 10:26 pm

Somehow we don’t have a sense of the vast difference between “water is necessary for life as we know it” and “the presence of water may mean that life exists.”

Michael S. Kelly
Reply to  d
October 31, 2020 10:47 pm

But the absence of presence doesn’t imply the presence of absinthe… or something profound, whatever…

Reply to  Michael S. Kelly
November 1, 2020 8:36 am

The absence of evidence is not evidence of absense. I believe that’s the quote you were thinking of.

Geo Rubik
October 31, 2020 11:19 pm

Water is only necessary for life as we know it. What about life as we don’t know it. We only consider life in our own context. What about life that is not like us.

Adam Gallon
Reply to  Geo Rubik
November 1, 2020 12:24 am

Find another bipolar, divalent solvent, that will do the job.

Dodgy Geezer
Reply to  Adam Gallon
November 1, 2020 1:12 am

A gaseous, plasma-based life-form may not need such a solvent at all. Hoyle’s ‘Black Cloud ‘ and Blish’s ‘Star Dwellers’ both describe such creatures…

Reply to  Adam Gallon
November 1, 2020 1:45 am

Nature goes for the most likely solutions.
This listcomment image
shows that H-O compounds are 3 x more likely than the H-N or 6 x more likely than H – C, all three (including N – O and C – O) being the fundamental life components on this planet.
It is possible that elsewhere in the universe their contribution to life is in a somewhat different proportions, which would make such living organisms based on fundamentally same chemistry but grossly different in appearance and functionality.

John Tillman
Reply to  Vuk
November 1, 2020 5:13 am

Liquid methane and ethane on Titan have been suggested.

Reply to  Vuk
November 2, 2020 9:42 am

Don’t forget Cu-O.
Arthropods and Molluscs rule.

And Mg-O.
Plants rule.

And Fe-O.
Something involving mammals, birds and reptiles.

Hemocyanin – Copper respiration
Chlorophyll – Mg Magnesium
Hemoglobin – Fe Iron respiration

Chemistry Works Thursday, August 12, 2010
Proteins are amino acid polymers. In addition to the protein part most of the proteins contains some non-protein component. Such proteins are known as ‘ conjugated proteins”. The protein part is known as “apoprotein”. The non-protein component is known as “prosthetic group”. If the prosthetic group is a metal atom then the conjugated protein is known as ” metalloprotein”.
Metalloproteins are classified on the basis of their function as follows:
Respiratory proteins
Electron transport proteins
Metal storage proteins
Catalytic proteins

These are metalloproteins which are involved in gas transport.
Example : Hemoglobin, Myoglobin, Hemerythrin and Hemocyanin.
Both hemoglobin and myoglobin are heme (prosthetic group) proteins containing Fe2+ . In higher animals hemoglobin transports oxygen from lungs to tissues. Myoglobin stores the oxygen in the tissues.
Hemerythrin and hemocyanin are the oxygen carrying proteins of lower animals. Hemerythrin is a nonheme iron containing protein.
Hemocyanin is a nonheme copper containing protein.

These are metalloproteins which are involved in electron transport. They are the components of electron transport chain (ETC).
Example: Cytochromes, iron sulphur protein and blue copper protein.
Cytochromes (a, b, c) are the iron containing heheproteins that act as electron carrier in all aerobic forms of life.
Iron sulphur proteins (Rubredoxin, ferridoxin) are nonheme proteins involved in electron transfer.
Blue copper proteins (stellocyanin, plastocyanin, azurin) are nonheme copper containing proteins involved in electron transfer.

These are metalloproteins which are used to store the surplus metal in nontoxic form.
Example: Ferritin, Transferrin (iron storage protein) Ceruloplasmin (copper storage protein).

Enzymes are otherwise known as catalytic proteins. Many enzymes contain metal ions as their structural component. Example: Cytochrome oxidase (iron and copper), Super oxide dismutase (copper and zinc), Nitrogenase (iron and molybdenum). These enzyme are bimetal complexes.”

C-O, i.e. Carbon-Oxygen oxygen compounds may be referred to as “organic”, but there is a lot more chemical compounds involved in life and various aggregations of compounds perform similar tasks.

Captain Climate
Reply to  Adam Gallon
November 2, 2020 1:46 pm

Dihydrogen sulfide

November 1, 2020 12:03 am

I have never understood why this is a mystery. Our sun (like all stars) normally emits a variable stream of plasma. The plasma consists of electrons, protons, probably neutrons (which decay in 15 minutes into protons and electrons), helium ions and small amounts of other light elements. So when protons (hydrogen ions) encounter oxygen, which is in abundance in rock and therefore, because of seismic events, gets into the atmosphere in some form including free O2 molecules, what do you think happens? Also I guess you would need to consider the speed at which this emitted plasma is going. It normally is from a few hundred kilometers a second to a few thousand kilometers per second. If it were going at 2 to 3 hundred thousand kilometers a second (like the stream from the center of the galaxy) then, of course the result would be quite different since the collisions of protons with oxygen would cause their breakup into smaller particles and not bonding to form H2O.

Reply to  Brent
November 1, 2020 3:58 am

You can see the solar wind reacting with oxygen in our atmosphere in the auroras. Reds and especially greens come from O2. With ionizing particles coming in constantly from the Sun, it isn’t hard to see water molecules being formed at high altitudes and being transported down. It would be a constant process and add up over millions of years. The term I’ve seen used is star water.

Reply to  rbabcock
November 1, 2020 8:32 am

Water vapor is also being disassociated in the upper atmosphere by solar UV & both oxygen and hydrogen then escape (in small amounts).

Patrick MJD
November 1, 2020 1:27 am

WOW! We found something in a rock on another rock that we found on this rock we live on!!!

Ron Long
November 1, 2020 2:08 am

Progressive crystal fractionation! See Wager and Brown: Layered Mafic Intrusions. As a planetary molten mass starts to lose heat it starts to crystallize. This crystallization begins with very high temperature crystals, like olivine, and proceeds through pyroxenes, feldspars, and quartz. Hydrous minerals generally start to appear in the feldspar to quartz transition, because it remains as an immiscible segregate in the melt until temperatures are reduced sufficiently. This progressive crystallization fractionation is due to higher temperature crystals having perfect crystal structures whereas lower temperature crystals having poorly ordered structures that tolerate imperfections. Think of these crystals as Republicans and Democrats, that might help visualization. Anyway, water appears out of a crystallizing planetary molten mess. Don’t need exotic sources.

Phil R
Reply to  Ron Long
November 1, 2020 5:20 am

Bowen’s reaction series.

Len Werner
Reply to  Phil R
November 1, 2020 5:57 am

Looks like I’m not the first to recognize the obvious–there indeed are research scientists who believe that water is a primary constituent of planetary formation. They’re called ‘geologists’.

Reply to  Len Werner
November 1, 2020 6:50 am

I think that granitic rocks have been detected by the MRO. If there are granitic rocks, water was present when they formed.

Reply to  Phil R
November 1, 2020 7:03 am

Brings back “fond” memories of igneous petrology… 🥃

Len Werner
Reply to  David Middleton
November 1, 2020 3:12 pm

Speaking of memories–I once got 110% on an undergraduate optical petrology exam. I had got everything else right, and one of the identifications was of scapolite. I found that I had not only enough information to positively identify the mineral as scapolite, but also where on the calcium-sodium continuous series this particular specimen sat–so included that. Damned if the prof didn’t give me a 10 mark bonus.

And–geologists will know that another, somewhat obsolete, name for scapolite is….Wernerite. Now what are the odds of that?

Phil R
Reply to  Len Werner
November 1, 2020 5:44 pm

My igneous petrology professor looked like Stalin; pointy beard, bushy eyebrows, bald head, and some of his students thought he actually was Stalin. one of the best teachers I ever had.

Bloke back down the pub
November 1, 2020 2:24 am

Hydrogen and oxygen are not exactly rare elements in the universe. Not unreasonable to expect water to be relatively common.

November 1, 2020 2:50 am

You can download the full paper here:
Deng, Zhengbin et al., “Early oxidation of the martian crust triggered by impacts“,

The main hypothesis here is that a huge (100km) object crashed into Mars about 4.4 Gy ago, melting the surrounding surface in which water was already present, releasing gases such as hydrogen which warmed the planet.

That would have left a huge impact crater which would still be visible today. Some craters/basins can be seen even with amateur equipment, say with a 125cm reflector or greater.

Maybe not the Hellas Basin (next to Syrtis Major), one of the largest, because it is thought to have been created only 3.8-4.1 Gy ago. But there are many candidates.

Randle Dewees
Reply to  Johanus
November 1, 2020 7:12 am

A 125cm (49″) telescope would be very unusual by amateur standards.

Reply to  Randle Dewees
November 1, 2020 7:29 am

… oops “125mm”. Thanks

November 1, 2020 4:18 am

Images from NASA’s Polar spacecraft provide new evidence that Earth’s upper atmosphere is being sprayed by a steady stream of water-bearing objects comparable to small comets…. Using Polar’s Visible Imaging System (VIS), a research team led by Dr. Louis A. Frank of the University of Iowa in Iowa City…

Louis Frank’s steadfast work to obtain these pictures is widely acclaimed. But not everyone accepts his interpretation of the data. There is not enough water apparent on the moon to satisfy some critics…

Water, water everywhere. Pluto, Mercury, Asteroids, the moons of Jupiter and Saturn. Now we discover it on both sides of Earth’s moon, lots of it. Forty years ago, Louis Frank discovered the flux of small comets that constantly bombard the earth and all the planetary objects.

When will we believe the data?


Dudley Horscroft
November 1, 2020 5:27 am

“Igneous clasts, or fragmented rock, in the meteorite are formed from magma and are commonly caused by impacts and oxidation,” said Mikouchi. “This oxidation could have occurred if there was water present on or in the Martian crust 4.4 billion years ago during an impact that melted part of the crust. Our analysis also suggests such an impact would have released a lot of hydrogen, which would have contributed to planetary warming at a time when Mars already had a thick insulating atmosphere of carbon dioxide.”

Perhaps the ‘oxidation’ occurred as a result of the presence of ‘oxygen’? You don’t need water for that. And surely hydrogen, like all the other two-atom molecules, is not a ‘global warming’ gas? And what evidence is there that Mars ever had a “thick insulating atmosphere of carbon dioxide”? I suppose it is possible that Professor Mikouchi explained all that in the full text, and that the press release was written by someone else?

Randle Dewees
November 1, 2020 7:43 am

50 grams would be roughly a 2cm block, just about the right size to make a thin section. I wonder if researchers do such old fashioned techniques anymore? I became involved with Star Wars funded CVD silicon carbide development in the early 90’s and with a couple thin sections pretty much showed everything wrong with the material (which was plenty) that couldn’t be seen with fancy modern techniques. It does consume some material, even the best slicer/dicer is going to need about a millimeter of thickness to get that 30 micron section, in this case about 400 mm^3 – which according to the article, can be worth $20,000!

Nick Schroeder
November 1, 2020 7:59 am

“Our analysis also suggests such an impact would have released a lot of hydrogen, which would have contributed to planetary warming at a time when Mars already had a thick insulating atmosphere of carbon dioxide.”


How does hydrogen warm?

“…already had thick atmosphere…” But it doesn’t have one a thick one now. The one it has now can barely be called an atmosphere. Where did the thickness go?

Sounds like a boat load of conjecture to me.

Robert of Ottawa
November 1, 2020 8:13 am

I have nevere understood the idea that water had to come from somewhere else. All the atoms to rpoduce it are available throughout the universe, it appears. I recall some years ago astronomers announcing the disscovery of a giant cloud of alcohol in teh galaxy, so why not water? If other chemicals can form at the same time in Earth, why not water? We have oceans of methane on other bodies in the solar sytem, so why not on Earth?

Reply to  Robert of Ottawa
November 1, 2020 8:52 am

Actually the paper assumes that all the water was already in place when a 100km wide object hit the planet 4.4 Gy ago. There is evidence, e.g. the Gale Crater Lakebed, that liquid water existed and flowed in great quantities at that time. For that to happen the atmosphere would have been thicker and warmer.

Mars does not have a magnetic field like Earth’s to protect its atmosphere. So it has eroded away and the current atmosphere is very, very thin (~7mb pressure at the surface) and very cold (210K, the same as its black-body temperature).

The paper claims that the impact created hydrogen, which somehow warmed the atmosphere above the water freezing point for millions of years. I did not see a clear explanation of how this works, but I just skimmed the paper. Molecular hydrogen (H2) is a dipole molecule, so is not greenhouse gas per se. But apparently it can ‘assist’ other GH gases by remove hydroxyl radicals (OH).

Ironically, this hypothesis seems to imply that CO2, which was abundant in that ancient atmosphere, did not have enough ‘umphh’ to do that kind of warming, i.e. melt ice. So no catastrphic warming for those ancient Martians, until H2 showed up..

Reply to  Robert of Ottawa
November 1, 2020 8:55 am

The theory is that the heat of the earth & other terrestrial planets was hot enough to vaporize/boil off most water during initial formation. The extremely-dry moon seems to support that as it was molten hot as it congealed & never had an atmosphere to stop UV from disassociating meteor-deposited surface water.

Steve Keohane
Reply to  beng135
November 1, 2020 2:38 pm
November 1, 2020 10:40 am

“Astronomers have known for decades that there is a lot of water in space. Hydrogen is the most common element in the Universe, and oxygen is made in stars and dispersed by events such as supernova explosions. The two elements mix in star-forming clouds and form large amounts of water (H2O). But because astronomers couldn”t measure gaseous water in cold clouds in space, they couldn”t be sure of the exact amount of water in those regions.”

So our Universe has a lot of Hydrogen. And older it gets, mind boggling amounts of Oxygen.
So something like 40% of mass of Mars is oxygen. The surface of all planets and our Moon has 40% of it’s mass being oxygen. All the mass of all rocky planets and asteroids in solar system doesn’t amount to much mass but roughly it’s 40% oxygen. Our Gas giants are mostly hydrogen, but are also considered to a lot liquid water in them.
Our sun make oxygen, our sun is common star, most stars are making oxygen. Some think H20 from H and O is made in reaction with dust {and other gases} in vacuum of space, and there is fair amount dust in our solar system- and tons of it rain down on Earth each year. Or after billions of years, probably a lot less dust in raining down on Earth per year. But intergalactic asteroids are entering our solar system, and probably also a lot dust enters our solar system, so over billions of years we could less dust and more dust in our system solar system. But when look star formations they in clouds of a lot of dust- so probably we started with a huge amount dust, and after planets formed, we reached low level of dust, and at that low level, it could have increased and/or decreased over the billions of years from dust coming from outside our solar system. Though when some planets collide** they could probably create a lot of dust. ** Particularly including planets [and/or other solar systems] coming from outside our solar system and hitting things at quite high velocity.

November 1, 2020 3:03 pm

Classic case of a weakness in science-relating to bias to one’s field.

Most ‘astronomical water’ theories come from astronomers who look upwards and not downwards, who are not granite geologists. Any magmatic geologist knows, when a magma cools it expels water. Cool 30km of crust over the entire planet during the formation of the planet and you get oceans. It’s not rocket science, and yet rocket scientists come up with the ‘water from asteroid/comet theory’ all the time, because that’s their field.

On planets below freezing this water remains locked up as ice, on planets closer to the sun like Venus it boils away, on Earth between 0-100C it forms oceans where basalt crust dominates because basalt is heavier and sinks, forming basins which then fill with water, called oceans.

Look beneath one’s feet for the answer, not up at the sky.

Reply to  thingadonta
November 1, 2020 5:52 pm

Chicken and Egg.
“In fact, granite is a “symptom” of a planet with vast, long-lived oceans, says John Clemens, a geologist at the University of Stellenbosch in South Africa. We also need plate tectonics to drag seawater, trapped in seafloor minerals, into the lower crust and mantle. “If you don’t have that process going on, then you’re never going to form granites, and you’re never going to form continents,” Clemens says, “and so it has not on Venus and Mars.” Indeed, Earth is the only planet in the solar system—and so far, the known universe—with granite rocks and continents.”

Reply to  gbaikie
November 1, 2020 6:13 pm

So, I had check if Mars had granite.
And apparently, Mars has some granite or granite like rock.
“Lead author James Wray, an assistant professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology, said that they’re providing the most compelling evidence to date that Mars has granitic rocks.”

Tom Abbott
November 1, 2020 5:11 pm

From the article: “There’s a long-standing question in planetary science about the origin of water on Earth, Mars and other large bodies such as the moon. One hypothesis says that it came from asteroids and comets post-formation. But some planetary researchers think that water might just be one of many substances that occur naturally during the formation of planets. A new analysis of an ancient Martian meteorite adds support for this second hypothesis.”

Well, the combining of asteriods and comets were what formed the Earth and Mars, and asteriods and comets have water in them, so that is where the water on Earth and Mars come from: From the basic building blocks of the Solar System, asteriods and comets, during planetary formation and after most planetary formation is done.

Mike McMillan
November 1, 2020 6:51 pm

I’ve always kinda wondered why they believe this rock came from Mars. Maybe it matches the other samples Neil Armstrong brought back when he planted the US flag that Sheila Jackson Lee asked if the Mars Pathfinder succeeded in taking pictures of in 1969.

Gotta luv Sheila. Making Houston look good and making the rest of us feel intelligent.

Reply to  Mike McMillan
November 2, 2020 10:41 am


November 2, 2020 5:42 am

PLEASE everybody- proof read your comments before you post them. Some of these are really hard to make sense of.

November 2, 2020 7:35 am

Something that amazes me is: how can we know that a meteorite found on Earth, that fell millions years ago… comes from Mars? How can we know that it comes from any particular place?

Reply to  Alejandro
November 2, 2020 1:10 pm

Obviously it would be impossible to tell where most meteorites originated, unless the number of possible sources can be vastly narrowed down by unusual or rare composition. That is the case for the so-called “SNC” meteorites, whose mineral content is named after the places they were discovered:
Shergottites => Shergahti, India, 1865: https://www2.jpl.nasa.gov/snc/shergotty.html
Nakhlites => El Nakhla, Egypt, 1911: https://www2.jpl.nasa.gov/snc/nakhla.html
Chassignites => Chassigny, France, 1815: https://www2.jpl.nasa.gov/snc/chassigny.html

There is a strong consensus among scientists that these rocks originated on a nearby planet (because hundreds of these have been found), almost certainly Mars, because they bear evidence of ancient geological evolution in the presence of water, with mineral and trapped gasses very similar to that found by our remote exploration of Mars.

Mercury is ruled out because it has no water (but there are other meteorites which are speculated to be from Mercury). Venus (and Jupiter, Saturn etc) also ruled out because of thick atmosphere and strong gravity. Similarly, asteroids are ruled out because they also have no water or geologically consistent composition.

Of course, there are many impact craters which can be seen on Mars, caused by collisions with large objects like the one described in the article above. A compressive force of 50 gigapascals will dislodge pieces of the surface with velocities exceeding 5km/s, sufficient to escape from Mars’ relatively weak gravity. (Earth gravity requires 11.19 km/s).

Numerous big collisions have occurred with all the planets, especially during the early development of the Solar System.

Of the 72,000 meteorites that have been officially classified, only 277 have been labeled ‘Martian’. Very likely many others may have originated from Mars too, but lack sufficient distinguishing features to be reliably classified as Martian.

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