Space

New study casts doubt on Mars valley formation theory

New study casts doubt on Mars ...
The Nili Fossae plains region on Mars, captured by the Mars Reconnaissance Orbiter
The Nili Fossae plains region on Mars, captured by the Mars Reconnaissance Orbiter
View 3 Images
The Nili Fossae plains region on Mars, captured by the Mars Reconnaissance Orbiter
1/3
The Nili Fossae plains region on Mars, captured by the Mars Reconnaissance Orbiter
The left-hand image is a color representation of data from the Mars Odyssey orbiter showing thermal readings of the area, while the image on the right displays mineral distribution in the Nils Fossae
2/3
The left-hand image is a color representation of data from the Mars Odyssey orbiter showing thermal readings of the area, while the image on the right displays mineral distribution in the Nils Fossae
Artist's impression of MAVEN orbiting Mars
3/3
Artist's impression of MAVEN orbiting Mars

A new study hasrevealed that during the period in which the red planet's distinctivevalleys supposedly formed, the Martian atmosphere may have alreadybeen too depleted to maintain the free-running water that it isbelieved to have carved out the geological features.

The Martian atmosphereis predominantly made up of carbon dioxide (CO2). It isbelieved that during the period of valley formation, a much greateramount of the gas was present in Mars' atmosphere, creating a denseshield that protected the Red Planet against the inhospitable spaceenvironment, and preventing water from instantly evaporating.

The new researchfocused on the largest deposit of carbonate (carbon which had beendrawn from the Martian atmosphere and locked into the ground)discovered on the Martian surface, Nili Fossae, bringing togetherdata from numerous missions surveying the Red Planet.

The results of thestudy cast doubt on the prevailing model of the Martian atmosphere atthe time of valley creation – "The biggest carbonate deposit onMars has at most, twice as much carbon in it as the current Marsatmosphere," states Bethany Ehlmann of the California Instituteof Technology and NASA Jet Propulsion Laboratory, Pasadena. "Evenif you combined all known carbon reservoirs together, it is stillnowhere near enough to sequester the thick atmosphere that has beenproposed for the time when there were rivers flowing on the Martiansurface."

The left-hand image is a color representation of data from the Mars Odyssey orbiter showing thermal readings of the area, while the image on the right displays mineral distribution in the Nils Fossae
The left-hand image is a color representation of data from the Mars Odyssey orbiter showing thermal readings of the area, while the image on the right displays mineral distribution in the Nils Fossae

Prior to the arrival ofprobes such as NASA's Mars Reconnaissance Orbiter, scientistsbelieved that many large deposits of carbonate such as that at NiliFossae would be present on the Martian surface, accounting for theCO2 that had previously, as part of the Red Planet's atmosphere,allowed liquid water to exist.

But according to thestudy, there would have to be at least 35 carbonate deposits the sizeof Nili Fossae close to the Martian surface to support the theory.The researchers state that such an abundance of carbonate is unlikelyto exist, as Nili Fossae is roughly the size of the state of Arizona,and that similar deposits would almost certainly have been detectedby satellite-based spectrometers.

But if Mars could notmaintain free running water in the creation period, just how were thevalleys cut into the Martian landscape?

"Maybe theatmosphere wasn't so thick by the time of valley network formation,instead of a Mars that was wet and warm, maybe it was cold and wetwith an atmosphere that had already thinned" explainsChristopher Edwards of the US Geological Survey in Flagstaff,Arizona. "How warm would it need to have been for the valleysto form? Not very. In most locations, you could have had snow and iceinstead of rain. You just have to nudge above the freezing point toget water to thaw and flow occasionally, and that doesn't requirevery much atmosphere."

Artist's impression of MAVEN orbiting Mars
Artist's impression of MAVEN orbiting Mars

The researchers pointout that it is possible that the atmosphere on Mars may have beendense enough to maintain liquid water at the time of valleyformation, and that the carbonate deposits simply aren't telling thewhole story. Another theory is that following the period of valleyformation, the carbon in the atmosphere was subsequently siphoned offinto space from the top of the atmosphere rather than locked into theplanet's surface via chemical reaction from the bottom.

This would leave notrace for instruments to find, and would create a workable model forthe Martian atmosphere for the period. It is possible that a relativenewcomer to the Red Planet, NASA's MAVEN orbiter, may shed light onthe conundrum as it observes the upper layers of Mars' atmosphere.

Source: NASA

4 comments
Wesley Bruce
There are two possibilities that most are not considering at NASA and other places. 1. The large northern plains are deep deposits of ice and carbonates covered with a thick layer of dust and long range volcanic ash. If that layer is several metres deep it could mask anything from a spectrometer. We need to drill that plains. 2. A mix of water ice, dry ice and dust forms a fast flowing glaciation process that leaves valley that look like they were cut by rivers. A combination of low gravity and differing mechanical properties of dry ice containing glaciers makes the valley look different than the U shaped glacial valleys of earth. Such glaciation would be driven by trapped gases pushing against still frozen masses of ice and dust. With a thick layer of permafrost on top the path of least resistance would be to grind the regolith and rock away down slope.
Nik
Perhaps the researchers should consider the 'electric universe' theories and the plasma arc cause of valleys, which would also explain the abundant 'blueberries' that are present on the Mars surface. If any of the researchers had ever carried out, as I have, or even watched arc welding, then the 'blueberries' would be explained as 'weld spatter' but on a massive scale. There are numerous characteristics on Mars that can be easily explained by plasma arc erosion, and with difficulty by any other method. There are several documentaries on 'youtube' that explain the various processes involved.
Benchkey
Am in agreement with Nick, the Electric Universe offers a superb explanation.
wilbo64
Mars old Moon was hit by Comet, debris hit surface ,formed valleys by impact, hinse no Moon no Metorology no or little surface life, long periods of no stable weather, just tectonics, oceans evaporated.