Navigating and mapping rivers has long been a central part of human exploration. Whether it was Powell exploring the Colorado Gorges or Pizarro using the Amazon to find El Dorado, rivers and our exploration were extremely important. Now scientists have designed a completely new, unique river basin. This happens to be on a completely different planet and dried up billions of years ago.
Three to four billion years ago, Mars actually had flowing water. Evidence of these rivers has shown up in satellite imagery and rover samples for almost as long as we’ve explored the red planet. Since Mars has little tectonics or erosion, that evidence has remained somewhat intact to this day.
Youtube video about the rivers of Mars.
Photo credit: Anton Petrov
Recently a team of scientists developed a tool to better study these characteristics. They managed to put together an 8 trillion pixel image of the entire surface of Mars. Each pixel in this incredibly detailed image represents an area of around 5 to 6 square feet. Unfortunately, it doesn’t seem open to the general public for even a year. Whether or not it does, it will surely prove useful in a wide variety of research projects relating to the Mars environment. One of the first, recently published in Geology, was a map of the red planet’s river crests.
The old dry river beds on Mars have been well mapped for some time, starting with Giovanni Schiaparelli’s famous “Canali”. However, there are other features of rivers that geologists like to study. One of the most important are the ridges described in the paper.
Some very detailed images of the Martian river systems as part of the 8 trillion pixel image of the surface.
Photo credit: JL Dickson et al.
River crests (or “river crests”) are caused by the sediment that a river carries away as it travels downhill. The sediment that a river ingests is occasionally ingested and deposited in various places, creating ridges that can become significant in size. Deltas such as those of the Nile and Mississippi are examples of this sediment deposition process.
Like the rivers on Earth, Mars had a similar process when liquid water ran on its surface. In the past, scientists had tried to inventory the river ridges using data from 1997 to 2006, but the data itself was not detailed enough to identify the types of features required for a full inventory.
Breathtaking picture of the Mississippi Delta. Similar river deltas would have existed on Mars billions of years ago.
Photo credit: NASA
These more detailed data have now been made available with the stitched-together image of the entire surface of Mars. Interestingly, only the planet’s southern hemisphere appears to have these ridges. The best explanation for this is that the northern hemisphere has resurfaced more dramatically in the past billion years, largely due to lava flows.
The southern hemisphere, on the other hand, is “one of the flattest surfaces in the solar system,” according to Woodward Fischer, one of the authors of the paper. These flat surfaces are ideal for viewing the ridges that would be created by sedimentation. It is easier to distinguish the additional material if the environment does not have significantly different altitudes within the framework of the natural geological features.
Schiaparelli’s original map of Mars with river basins and highlands.
Photo credit: Giovanni Schiaparelli
Not only is the study a really cool use for this new detailed map, but it’s also a helpful guide to the geological and ecological processes on Mars. Understanding where these ridges exist can potentially help guide future rover missions to a deposit of interest. Any additional information that can be gleaned from these sedimentation processes would be welcomed by the geological community. It can also contribute to our increasingly high-resolution understanding of the Martian surface. With this scientific goal in mind, the surveyor of the next great unexplored river system might just be a robot.
Learn more:
The Geological Society of America: River Mapping of Mars
Geology: The global distribution of debris flows on early Mars
American Geophysical Union: Global Map of the Mars River Systems: Estimates of Age and Total Eroded Volume
UT: Was that huge river delta on Mars the place where its oceans finally disappeared?
Mission statement: Example of river crests on Mars.
Photo credit: JL Dickson
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