Tag: MRO

Terraced mesas in Martian crater

12:38 pm

Terraced mesa in Martian crater
Click for full resolution image.

The cool image to the right, reduced and annotated to post here, was a captioned photo released by the Mars Reconnaissance Orbiter (MRO) science team earlier this week. Taken by MRO’s high resolution camera, it shows in color a beautifully stair-stepped mesa located in an unnamed 22-mile-wide equatorial crater in Arabia Terra, the large transitional zone between the lowland northern plains and the southern cratered highlands. As the caption notes,

Several craters in Arabia Terra are filled with layered rock, often exposed in rounded mounds. The bright layers are roughly the same thickness, giving a stair-step appearance. The process that formed these sedimentary rocks is not yet well understood. They could have formed from sand or volcanic ash that was blown into the crater, or in water if the crater hosted a lake.

If volcanic ash, the layers are signalling a series of equal eruptions of equal duration, which seems unlikely. Water is also puzzling because of the equatorial location. Like yesterday’s mystery cool image, water is only likely here at a time when the red planet’s rotational tilt, its obliquity, was much higher, placing this at a higher latitude than it is today.

Regardless, make sure you look at the full image here. This crater floor is chock-full of more such terraced mesas, some of which are even more striking than the sample above.

I have also posted below the MRO context camera photo of the entire crater.
» Read more

5 comments

A splat on Mars

2:23 pm

A splat on Mars
Click for full image.

Cool image time! The photo to the right, cropped to post here, was taken on October 31, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labelled simply as a “Terrain Sample”, it was not taken as part of any specific science research but because the MRO science team need to regularly take pictures to maintain the camera’s temperature. When such engineering images are required they try to pick spots of some interest, but sometimes the resulting picture is somewhat bland.

If you look at the full image, you will see that blandness generally describes it. However, in the upper left corner was a most intriguing-looking crater, which I have focused on above. From all appearances, when this impact happened the ground was quite soft, almost like mud, and thus the ejecta splattered away not as individual rocks and debris but as a flow.

The map below gives a little context, but really doesn’t explain this crater fully.
» Read more

5 comments

Cones on Mars!

9:35 am

Today’s cool image is actually a bunch, all found recently in the monthly image download from the high resolution camera on Mars Reconnaissance Orbiter (MRO).

All the photos I post below show pimple-like cones, all of which appear to be a type of small volcano. The cones are found in a wide range of locations, from the northern lowland plains to the cratered highlands to the mid-latitude transition zone between the two. They are also found at the bottom of deep canyons, in the floors of craters, and amidst mountains.

Let us begin.
» Read more

2 comments

Ancient and recent volcanoes on Mars

9:41 am

Volcanic vent on eastern flank of Olympus Mons
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on October 25, 2020. It shows what it calls a “possible volcanic vent east of Olympus Mons”.

Is this active? If not, how old is it. Also, the elongated shape of the vent suggests the possibility of a lava tube, or at least some underground complexity to the release of its magma.

In order to get some clarity, I emailed Sarah Sutton of the Lunar and Planetary Laboratory of the University of Arizona, who requested this photograph. Her response:

The image is of a small shield volcano with an elongated vent at the summit. We don’t have complete stereo here yet, so we can’t tell exactly what the height is. This vent might have sourced tube-fed flows, but in this case, we can’t resolve such features in the image data. This and other small shield volcanoes in the vicinity are partially buried by plains-forming lava flows. The lava flows around the base overlap the flows that emanate radially from the summit vent. Therefore we infer that the shield is older than the surrounding lava flows.

The vent, which runs from the southwest to the northeast, sits on top of a sloping wide hill, which is that small shield volcano described by Sutton. The flat plains surrounding this hill are from later eruptions from other and possibly larger volcanoes. The wider overview map below might give us a clue as to the source.
» Read more

One comment

Confirmed: Martian glacial features are ice

10:12 am

Lobate glacial flows on Mars
Click for full image.

Scientists using the radar instrument on Mars Reconnaissance Orbiter (MRO) have now confirmed that the Martian glacial features that most resemble the glaciers seen on Earth are made of substantial amounts of ice, and were possibly active and growing only a few million years ago.

“Our radar analysis shows that at least one of these features is about 500 meters thick and nearly 100 percent ice, with a debris covering at most ten meters thick,” said Berman, lead author of “Ice-rich landforms of the southern mid-latitudes of Mars: A case study in Nereidum Montes” published online in Icarus at https://doi.org/10.1016/j.icarus.2020.114170. PSI scientists Frank C. Chuang, Isaac B. Smith and David A. Crown are co-authors on the paper.

Global mapping of Viscous Flow Features (VFFs), a general grouping of ice-rich flow features in the southern hemisphere of Mars shows a dense concentration in Nereidum Montes, along the northern rim of Argyre basin. Located within a northwestern subregion of Nereidum Montes is a large number of well-preserved VFFs and ice-rich mantling deposits, the paper says, potentially the largest concentrations of any non-polar region in the southern hemisphere.

…Processed data from the Shallow Radar (SHARAD) instrument aboard NASA’s Mars Reconnaissance Orbiter spacecraft were used to search for basal reflections across VFFs within the region. For one in particular, these observations and analysis indicate that it is composed of nearly pure water ice. Model ages obtained from crater counts and their associated size-frequency distributions (SFDs) on both ice-rich mantling deposits and small lobate VFFs suggest that the deposits stabilized several to tens of millions of years ago in the Late Amazonian Epoch, and that small lobate VFFs likely formed due to the mobilization of mantling deposits.

This data here reinforces the impressions from many other places within the 30-60 degree latitude bands on Mars where many such features are found.

Mars might be a desert, but it is a desert like Antarctica, not the Sahara. Any settlement there must use the Earth’s south pole as its guide for construction and design.

6 comments

Strange crater in the basement of Mars

12:25 pm

Strange crater in Hellas Basin
Click for full image.

Today’s cool image to the right, cropped and reduced to post here, is intriguing for a number of reasons. Taken on September 11, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), it shows a partially buried crater found in the middle of Hellas Basin, the lowest point on Mars and what I like to call the red planet’s basement.

What makes this crater intriguing is the layered pile of material filling its interior. If I didn’t know any better, I would think some construction crew has used a bulldozer to push debris from the crater’s right half in order to smooth the ground in preparation for building a strip mall, office building, or housing development.

This of course is not what happened. Then what did create those layered piles in the crater’s left half?
» Read more

One comment

Cryptic Terrain on Mars

1:01 pm

Cryptic terrain near Mars' south polar ice cap
Click for full image.

Cool image time! The photo to the right, rotated and cropped to post here, was taken on September 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what is likely a crater that is partly buried by ice and dust and sand near or on the edge of Mars’s south polar ice cap.

It also shows an example of what planetary scientists have dubbed “cryptic terrain,” found generally on the margins of that ice cap. In this case, the location is on a plateau adjacent to the ice cap dubbed Promethei Planum. Despite a lot of searching, I could not locate any research papers describing Promethei Planum, though data outlined in one Mars Express press release from 2008 suggested it was part of the polar ice cap more than two miles thick that is covered by a thin mantle of dry ice each winter.

The strange curlicue cliffs and plateaus seen here are thought to form as part of the arrival and then sublimation away of that seasonal dry ice mantle, but how that process exactly works to create these particular geological features remains I think a mystery. North is to the top. The general grade is also downhill away from the icecap to the north.

Moreover, the overview map below, with the location of this image indicated by the blue cross, illustrates more mysteries.
» Read more

One comment

Terby Crater and its drainages into Mars’ basement

1:59 pm

Channels in Terby Crater on Mars
Click for full image.

Cool image time! Over the past few years, in my endless rummaging through the archive of high resolution images from Mars Reconnaissance Orbiter (MRO) I have posted a lot of photos of meandering channels of all kinds, most of which evoke to Earth eyes canyons eroded by flowing water. (This September 2020 cool image is just one of the more recent examples.)

Today’s cool image is another example, but in this case it is only a very small part of a very large drainage basin that is more than a hundred miles across and extends at least that far southward into the basement of Mars, Hellas Basin, the place on Mars with the lowest elevation.

The photo to the right, rotated and reduced to post here, was taken on September 12, 2020 by the high resolution camera on MRO. I normally wouldn’t post the whole image, but to crop it would mean you wouldn’t get the sense of extensive nature of this drainage. Downhill is to the south. The channel apparently passes through three or four stages. First, its northernmost section is in a wide canyon, the floor of which resembles glacial debris (though with a latitude of 27 degrees south this is a bit too close to the equator for ice). More likely we are looking at wind-blown sand and dunes being pulled downhill in the floor of the canyon.

This first canyon is also actually a gap in the rim of a 13-mile-wide unnamed crater. See this MRO context camera image for a wider view.

Next, the drainage becomes a series of meandering small interweaving channels, resembling the channels often seen in beach mud as the tide goes out.

Finally, the channels head into a gap to fall over a sloping cliff into lower terrain.

Nor these stages entirely linked. The first glacial-like stage exiting the gap in the crater appears to drain to the southeast, while the second seems to emanate from what appears to be a very faint small crater now partly buried. Both head south toward the gap, but the path of the eastward drainage appears less obvious. Some of it flowed westward to join the meandering channels but some also appears to work its way south more to the east.

This one image shows a lot of channels, but it is only a very small slice of this whole drainage system. In fact, we are looking here at only one strip of the interior slope of the northern rim of 108-mile-wide Terby Crater.

The overview map below gives the larger context. Terby Crater sits on the northern border of Hellas Basin, which in itself extends another 1,500 miles to the south. From this point the drop in elevation into Hellas is almost four miles.
» Read more

Leave a comment

Aram Chaos: Illustrating the puzzle of Mars

11:20 am

Aram Chaos
Click for full image.

The geological history of Mars is incredibly complex, and we really don’t know much about it. What we do know right now is based on a limited number of tiny fragments of a much larger story, with those fragments allowing scientists to only make educated guesses on how they fit together.

Many of those guesses will certainly turn out right. Just as many will turn out wrong. At this moment in our exploration of the Red Planet we can only grasp at straws while always keeping an open mind, as later data is surely going to change any conclusions we presently have.

The photo to the right is a good illustration of this struggle. Rotated, cropped, and reduced to post here, it was taken on September 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what at first glance looks like a stream of white frost or ice descending down a canyon to the south.

That first impression however is entirely wrong. When I asked Chris Okubo of the U.S. Geological Survey, who requested this image from MRO, what it was, he explained,

The white material is not frost. Instead, these are sedimentary rocks comprised primarily of sulfates. The texture to me suggests these are lithified dunes.

Lithified merely means that the dunes have hardened into rock. Sulfates are a salt formed from sulfuric acid, and are on Mars often linked to some complex mineralogy. If you stood there the colors would be white and red, quite beautiful. As Okubo explained,

The sulfates are white to tan in color, but there would also be a lot of red/brown Mars dust on top of it. It would be similar to walking around some of the playas in the desert southwest.

Though these white sulfate deposits have their root in sulfuric acid, Okubo added that they “are in the form of minerals similar to gypsum and so they would be safe to touch.”

What is going on here? As is usually the case, we need to first take a wider view to get some context.
» Read more

Leave a comment

Sagging cliffs on Mars

11:20 am

Sagging escarpment on Mars
Click for full image.

Cool image time! On Mars things change, but not like on Earth because the atmosphere is not as thick and there is no flowing water. The photo to the right, rotated, cropped, reduced, and annotated to post here, gives a good example of that slow change. The image was taken on August 29, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows the high escarpment that in this one place separates the planet’s southern cratered highlands from the transition zone down to northern lowland plains.

In this spot that escarpment, approximately 4,000 feet high, shows signs of avalanches and sagging. In the upper steep section, I point to what looks like a dust avalanche that wiped the slope clear of rough terrain as it rolled downhill. At the bottom of the cliff a large section has separated away. Since this cliff is located at 28 degrees north latitude and is in the midst of the chaos terrain regions I like to dub glacier country, it is very possible that this large section is actually buried glacial ice that in shifting down slope cracked, separating the lower section from the upper.

This particular location is east of an area dubbed Nilosyrtis Mensae (where there is a lot of evidence of glaciers and frozen ice), and about 650 miles north of Jezero Crater, where the rover Perseverance will land on February 18, 2021.

Leave a comment

A spray of Martian meteorites

12:27 pm

A spray of small secondary impacts
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on October 26, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It is what the camera team calls a “terrain sample,” meaning it was not specifically requested by a researcher but was instead chosen by the camera team because they need to regularly take images to maintain the camera’s temperature. When they do this, they try to pick a location that hasn’t been photographed in high resolution previously, and that might have some interesting features. Sometimes the photo is boring. Sometimes they hit pay dirt.

In this case, the photo captured an small impact crater, about 1,300 feet across, surrounded by a spray of secondary impacts. The color portion of the image shows what I suspect are dust devil tracks cutting across a surface that, because of its blue tint, is either rough or has frost or ice within it. At 48 degrees north latitude, the possibility of the latter is high, especially because this location is northwest of the Erebus mountains, where SpaceX has its prime Starship candidate landing zone and where scientists suspect ice is readily available very close to the surface. The overview map below shows this context.
» Read more

2 comments

A place on Mars where lakes, snowfall, and rivers once existed

2:19 pm

Inverted channels near Juventae Chasma
Click for full image.

Cool image time! The photo to the right, cropped and enhanced to post here, attracted my immediate interest when I was going through the November image dump from Mars Reconnaissance Orbiter (MRO) because of its meandering sharp ridges, estimated to be about sixty feet high on average. While I have previously posted MRO images of inverted channels such as these, their particular sharpness, plus their large number in this localized single image, aroused my curiosity. What is their history? Does this illustrate an particularly interesting place on Mars?

The picture itself was taken was on September 29, 2020 by MRO’s high resolution camera. The blue areas in the color strip probably indicate coarser-grained surface. This makes sense, as these ridges are believed to have been initially carved as channels by flowing water or ice, which compressed their riverbed and thus made it resistant to erosion. Over time, the surrounding terrain eroded away, leaving that channel behind now as a upstanding ridge. The surrounding eroded terrain should thus be expected to be rougher.

Where did the water for these rivers come from, however? As always, the overview maps below give the context, and a possible explanation.
» Read more

2 comments

Eroded and possibly wet Lohse Crater

2:51 pm

Gully flow near central peak of Lohse Crater on Mars
Click for full image.

Cool image time! Today we take a look at one particular 100-mile-wide crater, Lohse Crater, located in the southern cratered highlands on Mars. The photo to the right, cropped and reduced to post here, focuses in on one of the many eroding gullies found in the mountainous region surrounding the crater’s central peak. Taken on August 20, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), the full image is centered on that central peak, just off the south edge of this cropped section. This new image is part of a long monitoring campaign, begun in 2007, of this central peak region. For more than six Martian years, scientists have been tracking the numerous gullies found throughout the central peak region to see if there have been any changes.

I focused on this specific gully because I think it illustrates well why planetary scientists are monitoring these gullies. Whatever flowed down from the cliff on the left hit the material on the right hard enough and fast enough to imprint a curve into the material on the crater floor. Moreover, it does not appear to have simply been a landslide, for several reasons. First, the cliff does not appear cut back at the flow’s head, as you would expect if a section had broken off. Second, the material in the flow does not look like debris from an avalanche. In fact, there does not appear to be very much debris in the gully at all.

Third, and most important, the flow appears to originate at the cliff base, kind of what you’d expect if there was seepage coming out of a layer in that cliff face. Kind of what you’d expect on Earth, at a spring!

Was that flow water? This is the big question. Lohse Crater is significant in that it was one of the first locations on Mars [pdf] spotted by Mars Global Surveyor in the late 1990s where gullies were found suggesting some form of regular erosion possibly caused by flowing water. As this 2005 paper then concluded,
» Read more

3 comments

Giant wind eddies in the sands of Mars

12:13 pm

Wind eddies on Mars
Click for full image.

Cool image time! The image to the right, cropped and reduced to post here, was photographed by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on August 5, 2020. It shows a cluster of the crescent-shaped gullies, apparently carved from desert sand by the prevailing winds.

Those prevailing winds here are from the southwest to the northeast. As the wind blows the sand to the east, it hits a more solid object, such as a mountain buried in the sand, which forces the wind and the blown sand to go around, much as water passes a boulder in river rapids. That solid object also causes an eddy to form at its face, the wind forced downward and then around and up, carving out the gullies by lifting the sand at the base of that solid object. The result are these crescent gullies, dubbed blow-outs.

The overview map helps explain why there is so much sand here, enough apparently to bury whole mountains.
» Read more

3 comments

Glacial eddies on Mars?

12:24 pm

Glacial eddies on Mars?
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on August 15, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a truly strange bunch of blocks beside a clean flow neatly organized in almost straight parallel lines.

What is going on? This location is at 38 degrees south latitude, a latitude where scientists have found a lot of features that resemble water ice glaciers, generally protected from sublimating away by a thin layer of dust and debris.

A first guess is that the smooth glacial flow at the lower right is disturbing the glacial material next to it, causing it to rip apart and break up. At the same time, the hollowed look of these glacial blocks suggests that the ice below that protective debris layer is also slowly sublimating away, causing the surface to sink.

The wider shot below helps confirm this impression.
» Read more

Leave a comment

Frost on a Martian hillside

3:02 pm

Frost on Martian hillside
Click for full image.

Cool image time! The image to the right, cropped to post here, was taken on August 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a flat-topped mesa in an enclosed canyon dubbed Sisyphi Cavi in the high southern latitudes of Mars during the spring.

Notice the white spots in the gullies on the southern-facing slopes? From what I can gather from a bit of research, these indicate the presence of carbon dioxide frost. It was spring at this location when the photo was taken. At that time, the thin seasonal mantle of dry ice that covers Mars’ the polar regions south to 60 degrees latitude in the winter is sublimating away. This would explain why the frost is only present in the south-facing slopes. Since this is in the southern hemisphere, the south-facing slopes get much less sunlight, and would sublimate away later.

The photo was taken as part of a monitoring program to study this sublimation process. According to this abstract:

Superposition of channel features over and/or through the defrosting CO2 snowpack shows that the channels are active at the present day and probably have fluid flows every spring during the annual defrosting. In itself, this is a significant observation as active fluid flows of any nature have not yet been proven on Mars. However, the ambient temperature at the time of gully activity appears to require a role for CO2 in the formation of the channels, rather than water.

In other words, the coming and going of this dry ice frost each Martian year, in conjunction with the underground water ice also found here, appears to be causing erosion that then creates of the gullies themselves. More details from the abstract in this paper:
» Read more

Leave a comment

Buried mountain on Mars

2:17 pm

Isolated buried mountain on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 8, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled merely as a “terrain sample,” it is an example of an image taken more for engineering than scientific reasons. No research scientist specifically requested it. Instead, the scientists operating the camera took it because they need to use MRO regularly to maintain the camera’s proper temperature. To do this they periodically take almost random images, but never without trying to pick a location that might have some scientific value.

In this case we get what appears to be an isolated sloping hill. Located at about 15 degrees north latitude, this is not a place where one would expect visible evidence of water, though the gullies on the slopes are intriguing. They almost look like the kind of hillside erosion you see in places where rain falls on desert mountainsides.

Rain can’t be the cause, but nonetheless monitoring these gullies for changes over time would be worthwhile science research. Since it appears no one is presently focused on doing it, anyone interested out there?

This mountain is actually far more isolated than this high resolution image suggests.
» Read more

8 comments

A majestic terraced butte on Mars

1:35 pm

Majestic butte on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on September 8, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows an outstanding terraced butte that would rival any of the similar buttes scattered throughout the Grand Canyon, and is reminiscent especially of Wotans Throne.

What makes this butte intriguing are its terraces, the obvious result of the repeated deposition of new layers across the surface over time, and now exposed by erosion. What caused them?

As always, location provides the clues. First, this butte is found at about 15 degrees north latitude in the vast Arabia Terra transition region between the Martian northern lowland plains and the southern cratered highlands. At that latitude, we are not looking at any recent glacial features. While there might have been ice here once, it hasn’t likely been present, either on the surface or underground, for a very long time.

This conclusion becomes important once we look at the wider photo below, taken by the high resolution camera on the European orbiter Mars Express. This image gives us the immediate context.
» Read more

Leave a comment

A field of Martian knobs

12:30 pm

Knob field on Mars
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on August 9, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Uncaptioned, the image is merely dubbed a “knob field.”

I won’t spend much time trying to explain this geology. It might be related to pedestal craters, but these ridges and mesas don’t really look like those features, since they don’t really stand above the surrounding terrain.

Maybe they are a very ancient field of craters long buried, now partly exposed due to erosion, but also partly buried by wind-blown Martian sand and dust. Once again, that many of their shapes don’t resemble craters discounts this explanation.

The location of this photo is in the southern cratered highlands, as shown by the black cross in the overview map below.
» Read more

Leave a comment

Terraced mesa inside Martian depression

1:14 pm

Terraced mesa inside depression
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on July 1, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a very puzzling terraced mesa inside an enclosed depression or sinkhole (the western half of which can be seen in the full image).

What caused that mesa? A first scan of the image and the data suggests we are looking at sinkage related to the melting of an underground ice table. The latitude here is 34 degrees south, just far enough away from the equator for glacial activity to be possible. Moreover, the small circular depression in the upper right of the image strongly suggests an impact crater into slushy material. The implication is that this depression is the result of the melting or sublimation of underground ice, leaving behind a mesa that is made of solider stuff.

Another possibility is that the terraced mesa is actually the remains of glacial material. In the full image features inside other nearby depressions are terraced also, but are also much more reminiscent of glacial features found in many craters in the mid-latitudes. The depression is also close to the headwaters of Reull Valles, a meandering canyon where many images have shown glacial features (see for example here, here, and here).

These features however could also have nothing to do with water ice.
» Read more

Leave a comment

Why Martian mountains are different than on Earth

3:08 pm

A mountain peak on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 12, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what to any Earthling’s eye appears to be a somewhat ordinary flat-topped mountain peak with two major flanking ridgelines descending downward to the north and the south, and two minor ridgelines descending to the northwest and southwest.

This peak and its landscape would surely be quite a spectacularly place to visit, should humans ever settle Mars and begin doing sightseeing hikes across its more interesting terrain. I can definitely imagine hiking trails coming up the two minor ridges, with a crest trail traversing the main north-south ridge across the peak.

This is not however a mountain on Earth. It is on Mars, which makes its formation and evolution over time fundamentally different than anything we find on Earth, despite its familiar look.

First, what formed it? Unlike most of Earth’s major mountain chains, the mountains of Mars were not formed by the collision of tectonic plates, squeezing the crust upward. Mars does not have plate tectonics. Most of its mountains formed either from the rise of volcanoes at single hot spots, or from the wearing away of the surrounding terrain to leave behind a peak or mesa.
» Read more

3 comments

Layered mesa on Mars

2:41 pm

Layered mesa on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on June 24, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a distinctive mesa in a mountainous region in the cratered highlands of Mars, just north of Hellas Basin, the deepest basin on the red planet.

The mesa’s most distinctive feature are its terraced layers, a feature that MRO has found in numerous other places surrounding and inside Hellas Basin (see for example the cool images here, here, here, here, here, and here.)

On Earth the assumption would be that these terraced layers imply different sedimentary layers that erode at different rates, as best illustrated by the Grand Canyon in Arizona. On Mars that assumption is not unreasonable, but unlike Earth, those layers could not have been formed in connection with large ocean bodies creating seafloor layers from the deposit of sealife over centuries. Some other geological process over time formed them, with volcanism, either from volcanoes or impact, being the most likely.
» Read more

Leave a comment

A buried crater on Mars

3:35 pm

Close overview map

The overview map to the left indicates the general terrain surrounded today’s cool image. The white rectangle is the area covered by this image, taken on July 4, 2020 by the high resolution camera on Mars Reconnaissance Orbiter. If you look close you can see that this photograph covers the eastern rim of what looks like an ancient and mostly buried crater on Mars. This unnamed crater is about 17 miles across.
» Read more

One comment

Bringing life to the slumping lifeless slopes of Mars

12:05 pm

Slumping slopes on Mars
Click for full image.

To me, the cool image to the right, cropped and reduced to post here, helps illustrate the most significant difference between Mars and Earth, its obvious lack of life. This lack fundamentally changes the nature of erosion on the Red Planet.

On Earth life covers practically every square foot of the surface, and that life probably does more than anything to reshape the surface, and it does it far more quickly than any geological or meteorological process. For example, even if we are in the most lifeless area of the Sahara Desert, with no plant life, the dunes will still be reshaped and changed simply by the passage of any animal, whether it be a lizard, camel, or human driving a jeep.

On Mars, there is no visible life, and this lack means that any changes we see are solely geological or meteorological in nature. From a scientist’s perspective, the view is clean, all changes wrought solely by inanimate nature, without the added factor of life.

In a sense, Mars gives us a view of what geological and meteorological processes would do on Earth, if the Earth was lifeless.

Today’s image, taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on August 29, 2020, exemplifies this. Labeled “Slope Failures in Tempe Terra,” it shows the slow break-up and slumping of debris as it oh-so-slowly falls from higher terrain. The cracks developed as large chunks pulled apart as the material slide downward to the east.

This cracking took a lot of time. On Earth, during that time it would have either been obscured by plant life, or would have been distorted greatly by the traffic of animal life across its surface. Animals would have dug holes, and humans might have reshaped it to build homes and roads. On Mars, none of that happened, so the geology was free to evolve slowly, without interference, and now sits in plain view for scientists to interpret.

Such knowledge will over time strengthen our understanding of Earth geology, because it will give us a better understanding of the influences of life on that geology. Geologists will be better able to separate the influence of life and inanimate natural processes.

The overview map below helps give the wider context of those Martian inanimate natural processes, on a grand planetary scale.
» Read more

3 comments

“Flow-like” feature in the Martian lowlands

1:51 pm


Click for full image.

Cool image time! The photo to the right, rotated, cropped, reduced, and brightness-enhanced to post here, was taken on July 6, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

This is an uncaptioned image, labeled by the MRO science team as a “Flow-Like Feature in Chryse Planitia,” suggesting that they themselves are not exactly sure about what we are looking at. The latitude is 19 degrees north, which is a bit too far south for finding glacial features. Moreover, the craggy look of the ground here does not suggest an eroding glacier, but of eroding bedrock.

We could be looking at a volcanic feature, but this location is very far from Mars’ volcano regions. Nonetheless, another high resolution image, taken just to the west of this photo and given the exact same label, shows similar geology, and does strongly invoke a look of corroded lava flow.

The overview map below gives the context.
» Read more

2 comments

Was there a catastrophic flood in Kasei Valles on Mars?

1:45 pm

Overview map of lower section of Kasei Valles

Figure from paper

In our on-going exploration of Mars using the amazing high resolutions being taken by Mars Reconnaissance Orbiter (MRO), we return today to Kasei Valles, the drainage valley coming down from Mars’ giant volcanoes that I featured only a few days ago. And like that post, we must begin from afar and zoom in to understand what we are seeing in the final cool image.

Kasei Valles is a canyon system is about 1,900 miles long, and would cover two-thirds of the continental United States if placed on Earth. Its north-trending upstream section to the west and south of the area shown on the overview map to the right is thought to have been formed by some combination of glacial and volcanic processes. The downstream west-east section shown in the map instead appears to have been formed by a sudden catastrophic flood, which some scientists have theorized [pdf] occurred when a three hundred long ice dam broke suddenly, releasing the flood quickly across this terrain to create its features. The second map to the right, from their paper, illustrates this hypothesized event.

The white box in 60-mile wide Sharonov Crater near the center of the first map above indicates the location of today’s cool image below. The 1976 landing site of VIking 1 about 420 miles to the east is also indicated.

If you look closely at the first overview map above you can see that the rim of Sharonov Crater appears breached in its southwest quadrant, just to the west of the white box. This breach is less a break and more an area of increased erosion. Regardless, it sure appears that a massive flow pushed through the rim here.
» Read more

Leave a comment

The edge of Martian chaos

2:05 pm

Overview map of end of Kasei Valles

For today’s cool image, we are going to start from afar and zoom in, because I think that might be the best way to gain at least a rudimentary understanding of the strange geology visible at this one particular Martian location.

The first image, to the right, is the overview map. The red cross indicates our target, a chaotic canyon that flows into the larger Kasai Valles, one of Mars’ largest and longest canyons and possibly only exceeded in size by Valles Marineris. This part of Kasai is near its end, where it drains out into the vast northern lowland plains of Mars.

The second image, below, comes from the wide angle camera on Mars Reconnaissance Orbiter (MRO).
» Read more

One comment

Fingerprints on Mars!

12:53 pm

Fingerprint terrain on the Martian south pole icecap
Click for full image.

No, today’s cool image is not a variation of the absurd “face on Mars” that our alien-obssessed fantasy culture focused on for more than twenty years that turned out to be nothing more than a mesa whose shadows in one image made it look very vaguely like a face.

Instead, today’s cool image is of a very weird Martian geological feature that strongly resembles the whorls and curls seen in all fingerprints, and is thus apply named “Fingerprint Terrain.”

The photo to the right, rotated, cropped, reduced, and annotated to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter on August 26, 2020. It shows part of the surface of Mars’ south pole residual icecap, about 130 miles from the south pole, at a place where the temporary thin dry ice mantle that arrives every winter with the bulk of it sublimating away with the coming of spring.

The fingerprint in this image shows that sublimation process, with the gaps in dry ice mantle getting wider and larger as you move north, until the ridges between disappear altogether.

But why does it look as it does, like a fingerprint? In other places this sublimation process does not look like this at all. Sometimes we get spiderlike formations. Sometimes we get splatters that suggest geysers. Sometimes the surface sublimates to produce swiss cheese shapes. But why a fingerprint here?

I asked this question of Shane Byrne of the Lunar and Planetary Lab University of Arizona, who had requested this particular image, hoping he and other planetary scientists had investigated this geology and come up with an explanation. His answer illustrates how little we yet know about Mars.

It’s almost definitely some sort of sublimation process, but it hasn’t been well investigated. There are some papers that talk about sublimation landforms on the cap in general and map out where different types are, but nothing that I know that’s specific to the fingerprint terrain.

In other words, why the dry ice cap sublimates away in this manner, at this and other locations, remains unexplained.

I’ll say it again: Mars is strange, Mars is alien, and Mars is therefore a place humans must go.

14 comments

A massive Martian glacier that looks just like a glacier on Earth

2:06 pm

Massive glacier on Mars
Click for full image.

If you ever had any doubt about the existence of glaciers on Mars, today’s cool image should ease those doubts. The photo to the right, taken on August 27, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and rotated, cropped, and reduced to post here, shows many features that are appear identical to features found on typical massive glaciers on Earth.

Downhill is to the northwest. The many parallel grooves or fractures running along the length of the glacier resemble what are seen in many similar Earth glaciers. Some of these fractures are caused by the glaciers slow drift downward, with different sections moving at slightly different rates, thus causing a separation along the flow. Hence the parallel fractures.

These fractures also show evidence of some erosion. Because these Martian glaciers are no longer getting more snowfall, they are no longer growing. However, if the thin layer of dust and debris that protects the ice gets blown off or removed by motion, the ice is exposed and can then sublimate into gas so that the glacier erodes.

On the flow’s edges the darker parallel lines also resemble features seen on Earth, showing the exposed layers of the glacier’s past levels. The same thing can be seen on either side of the canyon’s walls.

The wide smooth section near the center of the parallel lines could very well be an impact crater that landed on this glacier sometime in the far past, and has since been distorted in shape as the glacier flowed downward.

If you still have doubts, the context image below, taken by MRO’s wide angle context camera, should help further allay those doubts.
» Read more

One comment

More Martian pits!

2:28 pm

Pit #1
Click for full image.

Pit #2
Click for full image.

Though the number of new pictures showing pits and possible caves from the high resolution camera on Mars Reconnaissance Orbiter (MRO) has significantly tailed off in the past year, as I noted in my previous post on Martian pits in September, the pictures are still rolling in. This post will highlight five new photos and the pits therein.

The first two, on the right, are both located on the southern flanks of the giant volcano Arsia Mons, where many such pits are found. They were taken respectively on August 16, 2020 and August 27, 2020. The first was a captioned image from MRO’s science team:

In this image, the ceiling of the lava tube collapsed in one spot and made this pit crater. The pit is about 50 meters (150 feet) across, so it’s likely that the underground tube is also at least this big (much bigger than similar caves on the Earth). HiRISE can’t see inside these steep pits because it’s always late afternoon when we pass overhead and the inside is shadowed at that time of day.

What I find most interesting about both images is that the skylights do not occur where you’d expect. In image #1, the meandering rill that suggests an underground lava tube is about 1,000 feet south of the pit. The pit itself seems unrelated to that rill. In image #2, the surface shows no obvious evidence of an underground tube matching the three aligned pits. There is the hint of a narrow depression along the alignment of the three pits, but this could just as easily be evidence of wind-blown dust along that alignment.

In the full image all three pits appear to sit inside a very wide and very shallow northwest-to-southwest depression, but this is hardly certain, and regardless the three pits align in a different direction.

The overview map below provides some context.
» Read more

Leave a comment
1 … 17 18 19 20 21 … 29