Dry Martian chaos
Click for full image.
On Mars, one of the most common kinds of landscape is called chaos terrain. Made up of mesas, buttes, and cross-cutting random canyons, this geology is not seen on Earth, and when first identified by scientists in early orbital pictures in the 1970s, it baffled them. While it is clear that some form of erosion process caused it, the scientists did not have enough data then to figure out what that process was.
Today scientists have a rough theory, based on what they now know about Mars’ overall geology and its climate and orbital history. The canyons of chaos terrain were originally fault lines where either water or ice could seep through and widen. See this January 2020 post for a more detailed explanation.
Most of the cool images I have posted of chaos terrain have been in places in the mid-latitudes that are covered with glaciers. See for example this December 2019 post of one particular mesa in glacier country, with numerous glaciers flowing down its slopes on all sides. That mesa is quite typical of all such mesas in the mid-latitudes.
Today’s cool image above, cropped to post here, takes us instead to the Martian very dry equatorial regions. The photo was taken on May 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and like mid-latitude chaos, it shows a collection of random mesas with canyons cut almost randomly between.
Unlike the mid-latitudes, however, there is no evidence of glaciers here. Instead, the canyons and mesa slopes are covered with dust, shaped into wind-blown dunes.
As always, the overview map below gives us some context.
The white cross marks the location of today’s image. Located in a chaos region dubbed Iani Chaos, this region is just south of the upstream end of the 1,100-mile-long meandering canyon dubbed Ares Valles. If water or ice once flowed down Ares Valley, it likely came out of Iani Chaos as it carved its canyons and buttes.
In trying to understand the geology in MRO photos, I am finding it increasingly amazing how helpful it is to know the latitude. When something is above 30 degrees latitude you will almost always see some evidence of near surface ice, either from an underground ice table or as buried glaciers.
Below 30 degrees latitude you will instead see no such evidence. Instead, the landscape will — like today’s photo — appear very dry, with the ground either hard bedrock or covered with dust and dunes. (See these two recent posts here and here for similar examples.)
That the nature of the Martian surface is so well determined by latitude is actually one of the more important discoveries scientists have uncovered about Mars in the past two decades. It not only tells them what to expect in each image, it provides some fundamental clues into the entire geological history of the red planet.
That history is not yet completely deciphered, but knowing this one simple fact will make finding the solution much 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.
Click for full image.
On Mars, one of the most common kinds of landscape is called chaos terrain. Made up of mesas, buttes, and cross-cutting random canyons, this geology is not seen on Earth, and when first identified by scientists in early orbital pictures in the 1970s, it baffled them. While it is clear that some form of erosion process caused it, the scientists did not have enough data then to figure out what that process was.
Today scientists have a rough theory, based on what they now know about Mars’ overall geology and its climate and orbital history. The canyons of chaos terrain were originally fault lines where either water or ice could seep through and widen. See this January 2020 post for a more detailed explanation.
Most of the cool images I have posted of chaos terrain have been in places in the mid-latitudes that are covered with glaciers. See for example this December 2019 post of one particular mesa in glacier country, with numerous glaciers flowing down its slopes on all sides. That mesa is quite typical of all such mesas in the mid-latitudes.
Today’s cool image above, cropped to post here, takes us instead to the Martian very dry equatorial regions. The photo was taken on May 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and like mid-latitude chaos, it shows a collection of random mesas with canyons cut almost randomly between.
Unlike the mid-latitudes, however, there is no evidence of glaciers here. Instead, the canyons and mesa slopes are covered with dust, shaped into wind-blown dunes.
As always, the overview map below gives us some context.
The white cross marks the location of today’s image. Located in a chaos region dubbed Iani Chaos, this region is just south of the upstream end of the 1,100-mile-long meandering canyon dubbed Ares Valles. If water or ice once flowed down Ares Valley, it likely came out of Iani Chaos as it carved its canyons and buttes.
In trying to understand the geology in MRO photos, I am finding it increasingly amazing how helpful it is to know the latitude. When something is above 30 degrees latitude you will almost always see some evidence of near surface ice, either from an underground ice table or as buried glaciers.
Below 30 degrees latitude you will instead see no such evidence. Instead, the landscape will — like today’s photo — appear very dry, with the ground either hard bedrock or covered with dust and dunes. (See these two recent posts here and here for similar examples.)
That the nature of the Martian surface is so well determined by latitude is actually one of the more important discoveries scientists have uncovered about Mars in the past two decades. It not only tells them what to expect in each image, it provides some fundamental clues into the entire geological history of the red planet.
That history is not yet completely deciphered, but knowing this one simple fact will make finding the solution much 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.
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