Click for full image.
Cool image time! Planetary geologists now think that the mid-latitudes of Mars contain many buried and inactive glaciers, formed several million years ago when the planet’s inclination was more than 50 degrees [pdf], rather than the 25 degrees it is now. At that time the mid-latitudes were actually colder than the poles, and water would sublimate from the poles to the colder mid-latitudes to pile up as snow and glaciers.
With today’s 25 degree inclination those mid-latitude glaciers are inactive, and have been so for several million years. It might even be that Mars’ water is beginning a shift back to the poles, but this is uncertain. If anything the planet is presently in a balance, and won’t start transferring water back to the poles until its inclination drops closer to zero.
The image to the right, taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) on September 23, 2019, is of one of those glacial flows, coming off a mesa in a region called Protonilus Mensae, located in the transition zone between the southern highlands and the northern lowland plains where an intermittent ocean might have once existed.
Much of the geology of Protonilus Mensae is chaos terrain, places where the surface has eroded along angled fissures to form many mesas. The overview map below focuses in on the particular mesa where this flow is located. The red boxes indicate all the MRO images taken of this mesa, with the image above indicated by the black dot.
You can see the chaos nature of this region by the many mesas, all separated by wide generally straight canyons. The blue area on the lower left is a large impact crater, its floor at a lower elevation.
The evidence that this area has many inactive glaciers is strongly reinforced when you look at the other three images taken of the slopes of this mesa, labeled #1, #2, and #3 on the overview map. Another image recently taken by MRO of another glacier in Protonilus Mensae to the east also supports this hypothesis. All these geological features resemble Earth glaciers, flows coming down canyons or hollows. All show evidence of a moraine at their feet, with the first image above even showing the merger of two glaciers at a confluence, similar the Concordia confluence of two glaciers in the Karakoram Mountains of Pakistan, near the world’s second highest mountain, K2.
A wider view of Mars gives further context. The map to the right shows the location of this mesa by the red dot in Protonilus Mesae. As already noted, this region is in that transition zone that might have once even been a shoreline to the ocean to the north.
The map also shows where Opportunity landed, as well as the planned landing sites for the European ExoMars 2020 rover and the U.S.’s Mars2020 rover, both scheduled for launch this coming summer.
The landing site for Mars2020 has many features strongly resembling the glaciers seen at this mesa at Protonilus Mensae, with the giant delta flowing into Jezero Crater especially intriguing. It might be a buried glacier, or cemented mud from water flow. The latter is more likely, as the latitude of this crater is around 18 degrees, putting it a bit south of the 30 to 60 degree latitudes where the buried glaciers have generally been found.
Regardless, the rover will see some breath-taking sites. And if it does find buried glaciers, all to the better. It will prove that these glaciers exist, and that water can be found in ample accessible places across the mid-latitudes of Mars.
Now available in hardback and paperback as well as ebook!
From the press release: In this ground-breaking new history of early America, historian Robert Zimmerman not only exposes the lie behind The New York Times 1619 Project that falsely claims slavery is central to the history of the United States, he also provides profound lessons about the nature of human societies, lessons important for Americans today as well as for all future settlers on Mars and elsewhere in space.
Conscious Choice: The origins of slavery in America and why it matters today and for our future in outer space
, is a riveting page-turning story that documents how slavery slowly became pervasive in the southern British colonies of North America, colonies founded by a people and culture that not only did not allow slavery but in every way were hostile to the practice.
does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.
“Zimmerman’s ground-breaking history provides every future generation the basic framework for establishing new societies on other worlds. We would be wise to heed what he says.” —Robert Zubrin, founder of founder of the Mars Society.
All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.
Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.