Sinkholes on Mars

For many reasons, mostly political but partly ethical, I do not use Google, Facebook, Twitter. They practice corrupt business policies, while targeting conservative websites for censoring, facts repeatedly confirmed by news stories and by my sense that Facebook has taken action to prevent my readers from recommending Behind the Black to their friends.
Thus, I must have your direct support to keep this webpage alive. Not only does the money pay the bills, it gives me the freedom to speak honestly about science and culture, instead of being forced to write it as others demand.


Please consider donating by giving either a one-time contribution or a regular subscription, as outlined in the tip jar below.


Regular readers can support Behind The Black with a contribution via paypal:

Or with a subscription with regular donations from your Paypal or credit card account:

If Paypal doesn't work for you, you can support Behind The Black directly by sending your donation by check, payable to Robert Zimmerman, to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652


You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage. And if you buy the books through the ebookit links, I get a larger cut and I get it sooner.

Caver alert! Releases this week from both the Mars Express orbiter and the Mars Reconnaissance Orbiter show a variety of sinkholes and collapse features on Mars, which in turn suggest the possibility of underground passages.

First, there is this picture from Mars Express, showing the area called Phoenicis Lacus (Latin for Phoenix Lake).

Phoenicis Lacus

The large and long canyon in box 1 is actually a collapse feature, almost two miles deep and formed as this region was stretched, warped, and cracked by the powerful volcanic activity of the nearby giant volcanoes of the Tharsis plateau, including Olympus Mons, the solar system’s largest volcano. You can also see how this activity causes several sinkholes and craters in all three boxes to become elongated and distorted.

In places where the surface is deformed in this way on Earth, you often find tectonic caves, underground cracks produced as the ground is pulled apart. The large collapse feature suggests the possibility that there are voids below it.

Then there is this subimage from this release of Mars Reconnaissance Orbiter, showing the central peak and southern slope of an old crater in the Terra Sirenum region of the Martian southern hemisphere.

central crater peak

Down that south slope can be seen what look like fluvial-like flows. In the center of these flows as well as near the top of the peak are what appear to be a string of collapse features. Below is the close-up as indicated by the box above:

inset closeup of sinkholes

From the caption: “It is possible that these pits are evidence of subsurface piping or hydrothermal activity. Piping occurs when subsurface water flows through soil, takes some soil with it, and causes the overlying ground to collapse. These fluvial-like features and the connected pits may have formed during a late stage of crater formation when temperatures were suitable for liquid water.”

On Earth, this is one of the geological processes that forms sinkholes on the surface as well as caves underground. When cavers go out to look or dig for new caves, we often head for just this kind of string of sinkholes, as they are excellent evidence that an unentered cave lies hidden below, ripe for exploration.



Leave a Reply

Your email address will not be published. Required fields are marked *