Tag Archives: Hellas Basin

The bottom of Mars

Hellas Basin ripples

Cool image time! The photo on the right, cropped and reduced to post here, was taken by the high resolution camera of Mars Reconnaissance Orbiter (MRO) on May 2, 2018, and shows some very strange ripples and erosion features in one of the lowest elevation locations on Mars, inside Hellas Basin. If you click on the image you can see the full photograph, at full resolution. There are a lot of strange features here, so make sure you take a look at it. The ripples highlighted in the image are between what appear to be three lower basins, and seem to my eye to be ridges created as liquid ebbed and flowed in the basins, depositing material at the shoreline at repeatedly higher and lower levels.

hellas basin

This particular location is not only in Hellas Basin, but it is also located in the deepest part of Hellas, a curved valley located in the basin’s northwest quadrant, as shown by the darker areas in the overview image to the right. The red boxes are other MRO high resolution images, with the cross indicating where this image is located.

This is the bottom of Mars, what could be called its own Death Valley. The difference however is that unlike Death Valley, conditions here could be more amendable to life, as the lower elevation means the atmosphere is thicker. The ripples also suggest that liquid water might have once been here, a supposition supported by other low area images of Hellas Basin, most of which show a flattish dappled surface that to me resembles what one would think a dry seafloor bed would look like The image in this second link also shows what looks like ghost craters that over time became partly buried, something one would also expect to happen if they were at the bottom of a lake, though this could also happen over time on Mars with wind erosion and the movement of dust.

It is also possible that these features come from lava events, so please take my theorizing here with a great big grain of salt. At the same time, recent results have found evidence of paleo lakes scattered all along the eastern rim of the basin, reinforcing the possibility that these were water filled lakes once as well.

Nonetheless, the ripples in the first image above are truly fascinating, as it is clear that at the highest peaks erosion has ripped those peaks away, leaving behind a hollow shaped by the ripples themselves. These features remind me of some cave features I have seen, where mud gets piled but by water flow, and then is over time covered with a crust of harder calcite flowstone. Later, water then washes out the mud underneath, leaving the curved flowstone blanket hanging in the air.

Here in Hellas Basin it looks like something similar has happened, except that at these peaks the outside crust got broken away, allowing wind to slowly suck out the material underneath, leaving these ripple-shaped pits. Whether it was liquid water or lava that helped create these features, the geology left behind is both beautiful and intriguing. I wonder at the chemical make-up of the crust as well as the materials below. And I especially wonder if there is water sources buried within Hellas Basin.

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The known ice cliffs on Mars

Last week there was a big NASA story about the discovery of eight locations on Mars where the evidence strongly suggests that these spots have cliff faces with exposed layers of water ice.

The press release however did not provide an overview about where those eight locations were. Only two locations were given, one for a scarp in Milankovič Crater in the northern hemisphere, and one in an area called Promethei Terra, located in the remote cratered highlands in the southern high-mid-latitudes.

The location of known ice scarps on Mars

After much digging (and some assistance from John Batchelor) I was finally able to obtain the latitudes and longitudes of all 8 locations. All but the scarp in Milankovič Crater crater (shown by the white dot north of Olympus Mons) are located in the white rectangular box shown to the south and east of Hellas Basin, the area with Mars’ lowest elevation. This part of Mars is not well imaged with the high resolution camera on Mars Reconnaissance Orbiter (indicated by the fewer number of red squares in the image), mostly because it appears relatively boring from a distance. Nothing appears to be there for hundreds and hundreds of miles except craters, sand, and sand dunes..

The discovery of these scarps in this area however changes the picture. It suggests that cratered highlands that surround Hellas Basin, including those close to the planet’s equator, could contain similar buried layers of ice. More research is necessary to pin down more locations, especially those closer to the equator where conditions might be more hospitable for a colony.

Moreover, educated readers of Behind the Black have previously noted that because of Hellas Basin’s low elevation the air pressure there is thicker, and therefore the location has some advantages as a potential colony location. These ice scarps raise the value of Hellas Basin considerably, as they suggest that such layers could easily be exposed as you descend into Hellas Basin. If such layers are exposed on the northern flanks of the basin, they would be at latitudes of around 25 to 30 degrees south, a much more friendly latitude for settlement.

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The Painted Desert of Mars

Mars Reconnaissance Orbiter released this picture yesterday of what the Orbiter’s scientists have labeled “The crazy floor of Hellas Basin.” Below you can see a cropped image of only one part of the large higher resolution image. The NASA caption says that the wild colors probably “indicate that diverse minerals are present,” meaning that any settlers of the red planet will probably take a close look at this location with the reasonable hope of finding the resources they need to colonize a planet.

To me, these colors also indicate that this place on Mars would probably one of its most popular tourist spots. As I look at the image my eye instinctively wants to trace out the best trail route along the ridges and down into the gullies in order to give hikers the best view of this colorful terrain.

Hellas Basin

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