Tag Archives: sinkholes
Mars Reconnaissance Orbiter has found another cave on Mars. The cropped version of the image, shown below, shows a remarkably symmetrical crater that probably has more similarities to sinkholes on earth. In the center is a 100 foot wide skylight into a cave. The crater is almost certainly formed partly by material dropping into the cave.
The discovery of new caves on the Moon keep coming. Today I have two new stories. The first is a discovery by professional scientists of a giant lava tube cave in the Oceanus Procellarum or Ocean of Storms. The second is the detection of a plethora of caves and sinks on the floor of the crater Copernicus, found by a NASA engineer who likes to explore the gobs of data being accumulated by Lunar Reconnaissance Orbiter and made available to all on the web.
The image below of the Moon’s near side, taken by India’s Cartosat-2A satellite and taken from the science paper, shows the location of lava tube in Oceanus Procellarum (indicated by the red dot) and the crater Copernicus.
First the professional discovery. Yesterday, the Times of India reported the discovery of lava tube more than a mile long on the Moon. I did not post a link to the article because I didn’t think the news story provided enough information to make it worth passing along. Today however, fellow caver Mark Minton emailed me the link where the actual research paper could be downloaded [pdf]. This I find definitely worth describing.
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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).
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.
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:
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.