Mars likely has many large and extensive cave systems
More caves on Mars! This week the Lunar and Planetary Institute and the Johnson Space Center are jointly holding the 50th Lunar and Planetary Science Conference in Texas. I have been going over the program, and will be posting reviews of some of the more interesting results all this week.
We begin with caves, which should not be surprising to my regular readers. As a caver who also knows their value for future space colonists, I am always attracted to new discoveries of cave passages on other worlds. Today’s however is a doozy.
The image to the right is of Mamers Valles on Mars, what scientists have dubbed a fretted valley, a common feature in the transition zone between the low altitude northern plains and the southern highlands. It comes from a paper [pdf] with the typically unexciting scientific title, “Fretted channels and closed depressions in northern Arabia Terra, Mars: Origins and implications for subsurface hydrologic activity.”
What the scientists really means here is that their research strongly suggests that Mars has a very large and very extensive number of underground drainage systems, which have caused collapses on the surface that often resemble meandering river canyons, such as seen above. As they explain:
Specific analysis of the largest fretted channel, Mamers Valles, reveals that the main channel floor incises into local topographic highs that should otherwise divert fluvial flow and prevent channel formation. Additionally, fracture patterns and slumping within the channel walls are observable at multiple points down-channel, suggesting removal of substrate support of the caprock unit. These observations, in conjunction with the paucity of effluent material near the Mamers channel mouth, support the interpretation that subsurface rather than surface flow is a major component of channel formation, producing fracturing of overlying plateau material and minimal observable sediment transport.
…Based on these morphologic observations, the fretted channels and closed depressions both appear to be inconsistent with formation through overland flow. Instead, the observed morphologies are interpreted to indicate a significant component of subsurface removal of material, based on (1) channel formation irrespective of surface topography, (2) pervasive evidence of collapse in both the fretted channels and closed depressions, (3) extended slumping of topography beyond the observed channel/depression cavities, and (4) the massive volumes of missing material required to produce the observed cavity volumes. [emphasis mine]
In other words, the meandering channel exists because such a meandering channel had existed underground, and as it formed and aged it caused the surface to sag or collapse above it. Much of that evolution the scientists theorized came from the melting of ice or snow.
From these observations, we consider five potential options for formation of the fretted channels and closed depressions capable of producing regional drainage and collapse: (1) sublimation/melting of a laterally extensive ice-cemented cryosphere, (2) sublimation/melting of lenses of buried snow and ice, (3) circulation and release of a liquid groundwater reservoir, (4) dissolution of highly soluble minerals (e.g., magnesium sulfates) and (5) some combination of the above.
They theorize that the melting was caused by heating from local volcanic events, of which there is ample evidence on Mars.
This conclusion has incredible implications for both Martian geology and future colonization. First, it could very well solve one of the biggest mysteries of Martian geology: The present surface geology suggests that a lot of liquid water once flowed on the surface, yet scientists have as yet not been able to figure out — based on what they know of Mars’s gravity and atmosphere either now and in the past — how this could have been possible. Mars was generally too cold or its atmosphere was too thin for liquid water to flow.
But what if a lot of that liquid flow was below the surface, in the ice table that other evidence suggests exists underground across much of the Martian surface? This in turn could explain a lot of the surface features on Mars, which we humans have assumed formed from surface flows, based on our Earth-based experience. Instead, maybe those Martian flows did not mirror what we would expect, but were instead Martian drainage systems underground and of a very alien design than what we are used to seeing. Earth for example has underground water drainage systems, most typically expressed in large cave systems. These however are rarely if never large enough to express themselves so obviously on the surface. On Mars however this might be very different.
The second important implication of this finding, and the one that is possibly more important, is that this research suggests that there are many many many underground voids on Mars, formed by water, that could be found in many places. Some might be easily accessible. Some might require drilling into. In either case, they would provide ample locations for building habitable colonies.
And they would likely still have that water, now frozen into the underground ice table.
The possibilities are mind-boggling. They suggest that everyone studying Mars must rethink the surface features. The alienness of Mars means they might resemble Earth geology, but might have formed in ways we have not previously imagined. And the consequences of that alien formation might make future human colonization far easier.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
More caves on Mars! This week the Lunar and Planetary Institute and the Johnson Space Center are jointly holding the 50th Lunar and Planetary Science Conference in Texas. I have been going over the program, and will be posting reviews of some of the more interesting results all this week.
We begin with caves, which should not be surprising to my regular readers. As a caver who also knows their value for future space colonists, I am always attracted to new discoveries of cave passages on other worlds. Today’s however is a doozy.
The image to the right is of Mamers Valles on Mars, what scientists have dubbed a fretted valley, a common feature in the transition zone between the low altitude northern plains and the southern highlands. It comes from a paper [pdf] with the typically unexciting scientific title, “Fretted channels and closed depressions in northern Arabia Terra, Mars: Origins and implications for subsurface hydrologic activity.”
What the scientists really means here is that their research strongly suggests that Mars has a very large and very extensive number of underground drainage systems, which have caused collapses on the surface that often resemble meandering river canyons, such as seen above. As they explain:
Specific analysis of the largest fretted channel, Mamers Valles, reveals that the main channel floor incises into local topographic highs that should otherwise divert fluvial flow and prevent channel formation. Additionally, fracture patterns and slumping within the channel walls are observable at multiple points down-channel, suggesting removal of substrate support of the caprock unit. These observations, in conjunction with the paucity of effluent material near the Mamers channel mouth, support the interpretation that subsurface rather than surface flow is a major component of channel formation, producing fracturing of overlying plateau material and minimal observable sediment transport.
…Based on these morphologic observations, the fretted channels and closed depressions both appear to be inconsistent with formation through overland flow. Instead, the observed morphologies are interpreted to indicate a significant component of subsurface removal of material, based on (1) channel formation irrespective of surface topography, (2) pervasive evidence of collapse in both the fretted channels and closed depressions, (3) extended slumping of topography beyond the observed channel/depression cavities, and (4) the massive volumes of missing material required to produce the observed cavity volumes. [emphasis mine]
In other words, the meandering channel exists because such a meandering channel had existed underground, and as it formed and aged it caused the surface to sag or collapse above it. Much of that evolution the scientists theorized came from the melting of ice or snow.
From these observations, we consider five potential options for formation of the fretted channels and closed depressions capable of producing regional drainage and collapse: (1) sublimation/melting of a laterally extensive ice-cemented cryosphere, (2) sublimation/melting of lenses of buried snow and ice, (3) circulation and release of a liquid groundwater reservoir, (4) dissolution of highly soluble minerals (e.g., magnesium sulfates) and (5) some combination of the above.
They theorize that the melting was caused by heating from local volcanic events, of which there is ample evidence on Mars.
This conclusion has incredible implications for both Martian geology and future colonization. First, it could very well solve one of the biggest mysteries of Martian geology: The present surface geology suggests that a lot of liquid water once flowed on the surface, yet scientists have as yet not been able to figure out — based on what they know of Mars’s gravity and atmosphere either now and in the past — how this could have been possible. Mars was generally too cold or its atmosphere was too thin for liquid water to flow.
But what if a lot of that liquid flow was below the surface, in the ice table that other evidence suggests exists underground across much of the Martian surface? This in turn could explain a lot of the surface features on Mars, which we humans have assumed formed from surface flows, based on our Earth-based experience. Instead, maybe those Martian flows did not mirror what we would expect, but were instead Martian drainage systems underground and of a very alien design than what we are used to seeing. Earth for example has underground water drainage systems, most typically expressed in large cave systems. These however are rarely if never large enough to express themselves so obviously on the surface. On Mars however this might be very different.
The second important implication of this finding, and the one that is possibly more important, is that this research suggests that there are many many many underground voids on Mars, formed by water, that could be found in many places. Some might be easily accessible. Some might require drilling into. In either case, they would provide ample locations for building habitable colonies.
And they would likely still have that water, now frozen into the underground ice table.
The possibilities are mind-boggling. They suggest that everyone studying Mars must rethink the surface features. The alienness of Mars means they might resemble Earth geology, but might have formed in ways we have not previously imagined. And the consequences of that alien formation might make future human colonization far easier.
Readers!
Please consider supporting my work here at Behind the Black. Your support allows me the freedom and ability to analyze objectively the ongoing renaissance in space, as well as the cultural changes -- for good or ill -- that are happening across America. Fourteen years ago I wrote that SLS and Orion were a bad ideas, a waste of money, would be years behind schedule, and better replaced by commercial private enterprise. Only now does it appear that Washington might finally recognize this reality.
In 2020 when the world panicked over COVID I wrote that the panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Only in the past year have some of our so-called experts in the health field have begun to recognize these facts.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
Mars is a vastly more interesting body to explore with rovers than the Moon.
Because it has an atmosphere, even if thin, I’m thinking the vast majority of future hi-res Martian exploration is likely to be done by drone aircraft. Particularly interesting spots could be explored, in detail, at ground level – or below – by suitable surface and/or tunnel rovers delivered either by drone aircraft landings or via parachutes.
https://en.wikipedia.org/wiki/Caverns_of_Mars
Been there, done that!