Tag: Olympus Mons

Thick windblown ash in Mars’ largest mountain region

12:35 pm

Thick windblown ash near Mars' largest volcano
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The cool image to the right, rotated, cropped, reduced, and sharpened to post here, was taken on September 1, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what the scientists label as “Erosional Features on Olympus Mons.”

What is eroding? Based on the picture itself the first guess is volcanic ash, as these features strongly resemble the many features seen in the Medusae Fossae Formation, the largest volcanic ash field on Mars — about the size of the subcontinent of India.

Medusae however is many thousand miles away, and is not apparently related to any specific volcano. These features are instead directly linked to Olympus Mons, the largest known volcano in the solar system. However, much of the terrain for many hundreds of miles around Olympus is covered with flood lava, which was deposited and hardened quickly to form smooth featureless plains that have resisted much erosion over the eons. Here the terrain is clearly eroded, which suggests that if the material here is volcanic, it was laid down not by flood lava but by falling ash that got compressed but was easily friable and could be blown away by the winds of Mars’ thin atmosphere.
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The northern interior rim of the largest volcano in the solar system

3:29 pm

Northern interior rim of Olympus Mons
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Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the northernmost interior rim of the caldera of Olympus Mons, the largest volcano in the solar system.

This one picture provides another way to illustrate the monumental scale of much of Mars’ topography. From the top to the bottom this steep scarp descends about 5,900 feet, in a little more than two miles. Compare that to the trails that descend the Grand Canyon’s south rim, which drop about the same distance but do it in distances ranging from three to five times longer.

In other words, this cliff wall is steep. Finding a route for a trail either up or down would be difficult at best.
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Ancient lava flows down the flanks of the solar system’s largest volcano

11:52 am

Lava flows on Olympus Mons
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Cool image time! The photo to the right, cropped, reduced, and sharpened to post here, was taken on October 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what appears to be very old and eroded lava on the northeast flanks of Olympus Mons, the largest volcano on Mars as well as the entire solar system. About 600 miles across, from the edge to its peak, Olympus rises about 54,000 feet, with an actual height relative to Mars’ “sea level” of just under 70,000 feet, more than twice as high as Mount Everest on Earth.

The white arrow show the downward grade. Several different flows can be seen throughout the picture, some confined to a central channel with smooth aprons of overflows on either side. Others are more broken and less coherent, and suggest that either the flows were inherently different, or are much older and have deteriorated with time.
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The highest point on Mars

12:41 pm

The highest point on Mars
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Today’s cool image is cool not because of anything visible within it, but because of its location. The picture to the right, cropped to post here, was taken on May 27, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). While the terrain shown is a relatively featureless plain of craters and gullies not unlike the surface of the Moon, what we are really looking at is the peak of Mars’ tallest mountain, Olympus Mons.

That’s right, this spot on Mars sits about 70,000 feet above Mars’ mean “sea level”, the elevation scientists have chosen as the average elevation on Mars from its center. At 70,000 feet, this peak is more than twice as high as Mount Everest on Earth.

Yet you wouldn’t really know you are at this height if you stood there. The scale of this mountain is so large that this peak, which actually forms the southern rim of the volcano’s 50 to 60 mile wide caldera, is actually relatively flat. If you stood here, you would not see the vast distant terrain far below. Instead, you’d see an ordinary horizon line in the near distance only slightly lower than where you stand.
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The gigantic lava flows off of the solar system’s biggest known volcano

12:50 pm

Olympus Mons' gigantic lava flow
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Cool image time! The photo to the right, cropped, reduced, and annotated to post here, was taken on October 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The picture covers a very tiny section of the southeast flank of Olympus Mons, the largest known volcano in the solar system. The arrow indicates the direction of the downward slope.

Olympus Mons itself is about 400 miles wide with an actual height relative to Mars’ “sea level” of just under 70,000 feet, more than twice as high as Mount Everest on Earth. The mountain’s flanks, almost 200 miles long from caldera edge to base, drop about 54,000 feet. That average drop of about 270 feet every mile is not particular steep, but its continuous nature over such a very very long distance makes its quite daunting.

You can see evidence of that slope in the photo. The downward pointing lobes each indicate the volcano’s last separate lava flows that ceased moving when each froze in place, probably several tens of millions of years ago. These lobes were also placed on top of many earlier flows from the volcano’s past eruptions that probably continued for several billion years, beginning 3.5 billion years ago.

The overview map helps provide a sense of scale by placing this image on that mountain flank.
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The steep sudden foothill of Olympus Mons

2:27 pm

Olympus Mons on Mars

Today’s cool image starts from afar and zooms inward. The elevation map to the right shows Olympus Mons, the largest volcano on Mars and in fact the entire solar system. About 600 miles across, from the edge to its peak this volcano rises about 54,000 feet, with an actual height relative to Mars’ “sea level” of just under 70,000 feet, more than twice as high as Mount Everest on Earth.

The cross-section of this volcano is so large it would cover almost all of France if placed on Earth. As a shield volcano, it was formed by many many volcano flows that laid down many layers of lava, with some in its northwest quadrant thought to be as recent as 2 to 115 million years ago.

Our cool image today is located at the white rectangle at the southeast edge of this volcano, and illustrates how those many lava flows could create such a large shield volcano with such a large cross section.
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Lava cones, fissures, and channels from Olympus Mons

9:11 am

A lava cone, fissure, and channel on Mars
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on June 29, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). In this one spot we see three obvious volcanic features, all however formed by different processes.

The location of this image is west of Olympus Mons. It sits on the vast lava plain that was laid down by that volcano, the largest in the solar system.

In order of likely occurrence, the cone probably came first. It likely indicates a past eruption coming up from below to create a small volcano.

The shallow meandering channel that sweeps around it to the north and east probably marks a later lava flow coming down from Olympus Mons.

The deeper straight fissure to the south probably came last. It is a graben, a crack caused by the uplift of the entire surface because of pressure from a magma chamber below, causing cracks to form as the surface is stretched.

Three different volcanic events, each probably taking thousands of years, with maybe thousands to millions of years between them. The context map below adds weight to the scale of time and size represented by this one Martian photo.
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Changing Mars

1:12 pm

The maculae splotch dubbed Maui
For the full images click here (2019) and here (2020).

While Mars appears to be a dead planet, with no clear evidence of life so far discovered, the planet is hardly inactive. Things are changing there continuously, even if it happens at a slower pace than here on Earth.

To the right are two images, rotated, cropped, and reduced to post here, taken by the high resolution camera of Mars Reconnaissance Orbiter. The first was on January 19, 2019, shortly after the end of the global dust storm that engulfed Mars during that Martian year. The second was taken on February 14, 2020, half a Martian year later. Both show one of a string of dark splotches located on the western flanks of the giant volcano Olympus Mons. Scientists call these splotches maculae, and because of their superficial resemblance to the islands of Hawaii, have given them names matching those islands. This particular patch is dubbed Maui. Below is a map showing all the splotches and their position relative to Olympus Mons, taken from a 2019 presentation [pdf].
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Sinkholes galore!

10:45 am

Sinkholes galore south of Olympus Mons
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Cool image time! The photograph to the left, cropped to post here, was part of the November image dump from the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a wind-swept dusty plain trending downhill to the west that is filled with more than a hundred depressions or sinkholes.

Unlike other pit images I have posted previously, this one is not focused on one particular pit or a string of pits. Instead, what makes it interesting is the large number of pits, scattered across the terrain in a random pattern. Their random distribution suggests that they are unrelated to any specific underground feature, such as a lava tube. Instead, some aspect of the underground geology here is causing the ground to sink at random points.

Below is an overview map showing where this dusty pit-strewn plain is located, indicated by the blue cross.
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Changes on the slopes of Olympus Mons?

12:15 pm

Dark splotches on slopes of Olympus Mons

Cool image time! In reviewing the many images from the October image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I came across two images, here and here, labeled “Change Detection in Olympus Maculae.” The image on the right is a cropped and reduced section of the first image, centered on the area of most interest. If you click on the image you can see the full photograph.

I did some research to see if I could find the changes indicated by this title. The location is an area on the outer western slopes of Olympus Mons, the largest volcano in the solar system. I found that MRO has taken images of this location twice before, in 2007, in 2009. I spent about fifteen minutes trying to find something that had changed, but was unable to locate anything, other than what look like a few wind-blown streaks probably caused by dust devils. I suspect I do not know what to look for.

Maybe my readers can spend some time and find these changes. If you do, please let us know in a comment.

Nonetheless, these two images revealed an area on the slopes of Olympus Mons that is most intriguing. It appears that there is a whole string of these dark splotches in this area, all of which have been carefully imaged by MRO several times. These splotches, along with the image titles, suggest that this might be area where there is activity from below that is causing the surface to darken. Could it be volcanic? Not likely. More likely is that there is underground frozen water located here, and like the spiders at the poles, this ice periodically pushes up as it sublimates to burst out as gas, and in the process darkens the surface.

If this guess on my part is correct, it suggests that this is an area in the mid-latitudes of Mars where water might be reasonably accessible. For future settlers this would be a significant discovery. And if my guess is wrong no matter. The features are puzzling, which explains why the scientists are aiming MRO at them repeatedly.

If I was to writing my science fiction novel Pioneer today, this is where I would have placed the discovery of the body of the Sanford Addiono, the astronaut who had disappeared on an asteroid near the orbit of Jupiter forty-six years previously. As the press release for the book’s release noted,

How Addiono had gotten to Mars from a distant lost asteroid–without a spaceship–was baffling.

That riddle was magnified by what Addiono had brought back with him. Among his effects was a six-fingered robot hand that had clearly been made by some alien civilization, along with a recorder and memo book describing what Addiono had seen.

What better place to put the start of this mystery but here, on a dark splotch on the slopes of Olympus Mons that also indicates its own geological mystery, a place some underground activity might be reshaping the surface of Mars.

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A dark dust avalanche on Mars

10:01 am

No dust avalanche

After dust avalanche

Cool image time! The two images to the right, both cropped to post here, were taken six years apart by Mars Reconnaissance Orbiter (MRO) of the western lava slopes of the giant volcano Olympus Mons. They show the appearance of a dark dust avalanche during the interim. As noted by members of the MRO science team.

Dust avalanches create slope streaks that expose darker materials usually hidden below a lighter-toned layer. Cascading fine-grained material easily diverts around boulders or alters direction when encountering a change in slope. The dark steak … is approximately 1 kilometer in length that we didn’t see in a previous image. Past avalanche sites are still visible and fading slowly as dust settles out of the atmosphere and is deposited on the dark streaks over time.

We also see boulders and their shadows that are a meter or greater in size. Movement of any of these boulders down the slope could trigger future avalanches.

The appearance of these Martian dark streaks on slopes is actually not uncommon. As more pictures are taken of Mars scientists are beginning to accumulate a large number all across the Martian surface.

What I find fascinating is the wet look of these dark streaks. Below is a close-up of the new avalanche, near its head.
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The epic lava flows of Olympus Mons

12:10 pm

Lava flows off of Olympus Mons

The eruption of Kilauea volcano in Hawaii has garnered a lot of deserved press coverage, having added at least a 200 acres of new land and destroyed at least 700 homes. Similarly, the recent violent eruption of a volcano in Guatemala, killing 100 people in its wake, has also gotten much deserved news coverage.

The magnitude of both however would pale in comparison to the stupendous eruption that occurred several hundred million years ago at the solar system’s largest volcano, Olympus Mons on Mars. While Kilauea is about 100 miles across, Olympus Mons is about 370 miles wide, and is so large that because of the curvature of Mar’s surface it is literally impossible for a viewer on the ground to actually see the volcano, in its entirety.

Both volcanoes are shield volcanoes, however, which means the lava flows don’t necessarily come from the caldera, but often from vents on the volcano’s slopes. Eruptions might be violent, but they generally do not involve the powerful explosive force of the sudden eruption, as seen in Guatemala and at Mount St. Helens in 1980 in the U.S. Instead, the lava seeps out steadily and continuously, an unstoppable flow that steadily overwhelms the surrounding terrain.

Olympus Mons

The flows that created Olympus Mons however were an epic event probably lasting millions of years, which brings us to this post. In the June release of Mars Reconnaissance Orbiter high resolution images, I found the image above, cropped and reduced in resolution to post here. It shows lava flowing down off one of the many escarpments on the slopes of Olympus Mons. This is not at the edge of the volcano’s shield, but just inside it. The map at the right, created using the archive of MRO’s high resolution camera, indicates the location of this flow, shown by the left light blue rectangle on the southeast slope of the volcano’s shield. The red rectangles show all the other images MRO has taken of Olympus Mons.

The scale of the MRO image above gives an indication of how big that eruption at Olympus Mons was.
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Massive flow on Mars

9:59 am

Massive flow on Mars

Cool image time! The image on the right, cropped to post here, comes from a Mars Reconnaissance Orbiter image that shows a massive relatively recent and dark slope streak that emanates out from a single point on the surface. (Note that the release at this link rotates the image so that north points down. I have rotated back so that north points up.)

Streaks form on slopes when dust cascades downhill. The dark streak is an area of less dust compared to the brighter and reddish surroundings. What triggers these avalanches is not known, but might be related to sudden warming of the surface.

These streaks are often diverted by the terrain they flow down. This one has split into many smaller streaks where it encountered minor obstacles. These streaks fade away over decades as more dust slowly settles out of the Martian sky.

Point of origin for flow

Location of flow, west of Olympus Mons

The MRO release focuses on the fingerlike breakup of the flow as it descends into sand-dune filled plain. What is more interesting to me is the terrain where this flow originated. A close-up of that area from the full image, shown on the right, reveals a feature that could be a wash running in line with the flow’s origin, and leading uphill to a dark feature that is a likely a cliff face. (The light in this image is coming from the southeast.)

This location, at 15.2N latitude, 214.9E longitude and shown by the small cross in the image on the right and captured from this page, is west of Olympus Mons, the largest volcano on Mars. This suggests to me that the originating feature might be an outlet from a lava tube, from which water suddenly seeped out to produce this massive slope streak. A look at the mesa from which this flow came, cropped from the full image and posted below the fold, shows numerous similar slope streaks of varying ages flowing out of this mesa, with some very faint because they occurred farther in the past. Some are even within the bowl at the top of the mesa.

Whether these come from lava tubes is definitely unclear, and I suspect I will be told by geologists not likely. The seeps however do suggest strongly that this mesa might be a very good location for future colonists to look for underground water ice. Since clouds form on the western slopes of Arsia Mons, the southernmost of the three giant volcanoes to the east of Olympus Mons, and that past glacial activity has been documented there, I wonder if some of these same conditions might also exist here, on the nearby terrain west of Olympus Mons.
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