Martian Fluvial Flows, Placid and Catastrophic

Despite the fact that, apart localized dust surfaces in summer, the surface of Mars has had average temperatures that never exceeded about minus 50 degrees C over its lifetime, it also has had some quite unexpected fluid systems. One of the longest river systems starts in several places at approximately 60 degrees south in the highlands, nominally one of the coldest spots on Mars, and drains into Argyre, thence to the Holden and Ladon Valles, then stops and apparently dropped massive amounts of ice in the Margaritifer Valles, which are at considerably lower altitude and just north of the equator. Why does a river start at one of the coldest places on Mars, and freeze out at one of the warmest? There is evidence of ice having been in the fluid, which means the fluid must have been water. (Water is extremely unusual in that the solid, ice, floats in the liquid.) These fluid systems flowed, although not necessarily continuously, for a period of about 300 million years, then stopped entirely, although there are other regions where fluid flows probably occurred later. To the northeast of Hellas (the deepest impact crater on Mars) the Dao and Harmakhis Valles change from prominent and sharp channels to diminished and muted flows at –5.8 k altitude that resemble terrestrial marine channels beyond river mouths.

So, how did the water melt? For the Dao and Harmakhis, the Hadriaca Patera (volcano) was active at the time, so some volcanic heat was probably available, but that would not apply to the systems starting in the southern highlands.

After a prolonged period in which nothing much happened, there were catastrophic flows that continued for up to 2000 km forming channels up to 200 km wide, which would require flows of approximately 100,000,000 cubic meters/sec. For most of those flows, there is no obvious source of heat. Only ice could provide the volume, but how could so much ice melt with no significant heat source, be held without re-freezing, then be released suddenly and explosively? There is no sign of significant volcanic activity, although minor activity would not be seen. Where would the water come from? Many of the catastrophic flows start from the Margaritifer Chaos, so the source of the water could reasonably be the earlier river flows.

There was plenty of volcanic activity about four billion years ago. Water and gases would be thrown into the atmosphere, and the water would ice/snow out predominantly in the coldest regions. That gets water to the southern highlands, and to the highlands east of Hellas. There may also be geologic deposits of water. The key now is the atmosphere. What was it? Most people say it was carbon dioxide and water, because that is what modern volcanoes on Earth give off, but the mechanism I suggested in my “Planetary Formation and Biogenesis” was the gases originally would be reduced, that is mainly methane and ammonia. The methane would provide some sort of greenhouse effect, but ammonia on contact with ice at minus 80 degrees C or above, dissolves in the ice and makes an ammonia/water solution. This, I propose, was the fluid. As the fluid goes north, winds and warmer temperatures would drive off some of the ammonia so oddly enough, as the fluid gets warmer, ice starts to freeze. Ammonia in the air will go and melt more snow. (This is not all that happens, but it should happen.)  Eventually, the ammonia has gone, and the water sinks into the ground where it freezes out into a massive buried ice sheet.

If so, we can now see where the catastrophic flows come from. We have the ice deposits where required. We now require at least fumaroles to be generated underneath the ice. The Margaritifer Chaos is within plausible distance of major volcanism, and of tectonic activity (near the mouth of the Valles Marineris system). Now, let us suppose the gases emerge. Methane immediately forms clathrates with the ice (enters the ice structure and sits there), because of the pressure. The ammonia dissolves ice and forms a small puddle below. This keeps going over time, but as it does, the amount of water increases and the amount of ice decreases. Eventually, there comes a point where there is insufficient ice to hold the methane, and pressure builds up until the whole system ruptures and the mass of fluid pours out. With the pressure gone, the remaining ice clathrates start breaking up explosively. Erosion is caused not only by the fluid, but by exploding ice.

The point then is, is there any evidence for this? The answer is, so far, no. However, if this mechanism is correct, there is more to the story. The methane will be oxidised in the atmosphere to carbon dioxide by solar radiation and water. Ammonia and carbon dioxide will combine and form ammonium carbonate, then urea. So if this is true, we expect to find buried where there had been water, deposits of urea, or whatever it converted to over three billion years. (Very slow chemical reactions are essentially unknown – chemists do not have the patience to do experiments over millions of years, let alone billions!) There is one further possibility. Certain metal ions complex with ammonia to form ammines, which dissolve in water or ammonia fluid. These would sink underground, and if the metal ions were there, so might be the remains of the ammines now. So we have to go to Mars and dig.







2 thoughts on “Martian Fluvial Flows, Placid and Catastrophic

  1. Reblogged this on Patrice Ayme's Thoughts and commented:
    Mars lost most of its magnetic field about four billion years ago (ours is doing fine to a massive nuclear reactor below our feet, keeping extremely fluid a titanic ocean of iron upon which Earth’s mantle floats…).

    As a result, solar wind and cosmic radiation have since not been deflected from hitting the Red Planet straight on. Instead, this terrible radiation interacts by direct slashing impact with the Martian ionosphere. We now know this happens mostly during the horrendous, but frequent, Coronal Mass Ejections. This constant whipping keeps the atmosphere much thinner than it would otherwise be as the solar wind action constantly tears away atoms from the outer atmosphere.

    Before the loss of (most of) the magnetic field, it’s considered that there was an ocean of water, on Mars.

    Should that be true, the possibility of life having started on Mars is very high. As Mars cooled faster than Earth, it’s possible that Martian life appeared hundreds of millions earlier than life on Earth. And that this life on Earth was actually Martian life, transported by impacts.

    After that, the planet died.

    Still, it’s mysterious: periodically its rotation axis tilts to 40 (forty) degrees. Then poles melt, and the atmosphere thickens…Could then temperature jump up? Could that explain the water flows observed on Mars (we know they are water flow, because, thanks to a French made laser on board Martian robot Curiosity, thousands of rocks have been blasted and their chemistry revealed!)

    So what about those massive flows on Mars?

    The massive flows seem to have happened 3,700 million years ago, during the early Hesperian.
    We know this by crater counts). Methinks that there was then water on Mars surface. Water, and ice. Massive outflows have happened on Earth as recently as 18,000 years ago (Younger Dryas, etc.) When massive glacial dams released oceanic sized sweet water lakes.

    I simply think that’s simply what happened on Mars. Simple is beautiful…

    Our friend Ian Miller, a research scientist with a long career, proposes a completely different mechanism, the science of which is beyond mine. If nothing else, this contrast between my hare brained simplicity in this matter, and Ian’s sophistication, shows the rich possibilities that working scientists have to consider, when trying to push science forward. And, by the way, even “failed” scientific models can be very useful (actually most ancient scientific models have “failed”, more or less… As they were replaced by more advanced science)

    Scienta: fluctuat, nec mergitur!
    Science is agitated by the waves, but does not sink!
    Patrice Ayme’

    • Thanks for the comment, Patrice. The bracketed piece in the first para is quite poetic. Well done. In my opinion, Mars has a negligible iron core. The density of Mars is about 3.8, which is the upper end of basalts, and even on Mars, the pressure will compress rock into its highest density stable form. During accretion, lumps of iron would also carry a lot of radioactive material that is soluble in it, so Mars probably missed out there too. I agree life may well have tried to get started on Mars, but the fluid systems appeared to not have lasted more than about 300,000 years in any one place, and I am not convinced that is enough time, but hopefully if we send people there we shall get an answer to that. I really think (or hope) that there may well be a roadmap there of various starts of life that got so far and stopped, but at different places. And yes, I agree – not only is simple beautiful, but I rather think nature’s principles are simple, although they can get complicated when there are multiple things happening.

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