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On the edge of Mars’ giant volcanic flood plain

Flows and pitted material on the edge of Mars' great volcanic flood plain
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on September 30, 2020 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Uncaptioned, it shows what the science team labels “Flows and pitted material in Terra Sirenum.”

Downhill is to the southeast, which means the pitted material forms some sort of filled terrain, with the surface eroded similarly everywhere. At a latitude of 32 degrees south, these flows could conceivably be glacial features. Are they?

A wider look might help answer that question. Below is a photo taken by MRO’s context camera, cropped and reduced to post here.

Context camera view
Click for full image.

The white box indicates the area covered by the first image above.

It appears that this flow feeds into a very vast sea of pitted material, which extends far beyond even this image (as can be seen by this adjacent context camera photo).

Is it possible this sea is all glacial? It seems unlikely. At this latitude any glacial features seen are never as pervasive or widespread as this. By 30 degrees latitude Mars appears to be drying out, and the glacial features are beginning to fade. In fact, scientists have seen almost no such features closer to the equator.

Furthermore, look at the craters both in this sea and outside it. They look somewhat the same, as if they were impacts in solid bedrock. Impacts on icy ground look far different, almost like splats.

The Tharsis Bulge

So, what are we looking at?

The wide overview map to the right might provide an answer. The white cross near the bottom center is the location of today’s image. It is apparently located at the very edge of the vast shield produced by the volcanoes that form what scientists have dubbed the Tharsis bulge on Mars.

In other words, this sea is likely a lava plain, and this particular spot is its shoreline. Instead of the flow going downhill into the sea, what we are looking at is a flow pushing into a break in the rim of the crater on the ridge. This interpretation also helps explain the nature of the flow in that crater. It seems to stop suddenly, as if the flow froze suddenly. Its nature seems to fit frozen lava better than frozen water.

While there still could be ice and glaciers scattered through this terrain, they do not appear to be the dominant feature. At least, that’s my guess. What’s yours?

Pioneer cover

From the press release: From the moment he is handed a possibility of making the first alien contact, Saunders Maxwell decides he will do it, even if doing so takes him through hell and back.

Unfortunately, that is exactly where that journey takes him.

The vision that Zimmerman paints of vibrant human colonies on the Moon, Mars, the asteroids, and beyond, indomitably fighting the harsh lifeless environment of space to build new societies, captures perfectly the emerging space race we see today.

He also captures in Pioneer the heart of the human spirit, willing to push forward no matter the odds, no matter the cost. It is that spirit that will make the exploration of the heavens possible, forever, into the never-ending future.

Available everywhere for $3.99 (before discount) at amazon, Barnes & Noble, all ebook vendors, or direct from the ebook publisher, ebookit. And if you buy it from ebookit you don't support the big tech companies and I get a bigger cut much sooner.


  • Lee Stevenson

    I can only agree with your analysis here Bob… And I’m getting more and more convinced regarding your galacial theory of water on Mars. There is no doubting that 2 or 3 billion years ago it would have been interesting to see what was occurring there, it will also be interesting to see the fossils the next generation of rovers find…. We all wish! Mars is a very alien planet, and we still have very much to learn about its history… Roll on February, and fingers crossed for every mission arriving at the red planet!

  • I think it is super-convenient we have a ‘practice’ planet right next door.

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