Tubes on Mars

Page 4

This is a section of Steve Windgates enhancement. Click on it to see a larger image. It is clearer reading and the formations are easier to see. I have annotated possible geological processes. Still I am not certain about any of this. There is one idea that I have not mentioned - some kind of root or Martian rhizoid plant. Now that is interesting. Could all these crazy, almost irrational, shapes found all over the planet be fossil plant material?

Roots?
See Article on Electric Warrior's Mars Online Site

There are a lot of ideas out there. But I am into geology. What geological forces can produce these structures? They look tubular in the MGS and MOC images. We are told what we are seeing is an optical illusion. And yet the craters in these images look quite the way they should - like holes. When viewed from the top of a deep dark canyon, perhaps this kind of structure can cause an inverted optical effect. But if you invert the image nothing else makes very much sense. The "tubes" look more like ridges and troughs. But all you are really doing is changing the light and shadow. The structures still have a lot of bulk to them. They still look rather tubular.

Crater and Younger "Tube". It is still forming or becoming exposed. The invert on the right.
What's wrong with this picture?

Image m040029a - - and its inverse

NASA says these are dunes. It would either take lot of material in suspension in a concentrated area, or a lot of wind moving around loose surface materials to produce these dunes. I suppose there could be quite a breeze blowing through those canyons, but I have to ask why dunes did not form above the canyons. Surely there is a bit of a breeze up there, and lots of material for dune making, as well as plenty of airborne particles. Too much wind on top perhaps? That does not seem to make sense either. These "tubes" are located in the margins of very big polygons, several hundred feet wide. We can't see the bottom as there is not enough light to penetrate those depths. Some "Tubes" do not seem to be located very deep in the fissure. Some seem to be just beginning to form at the top. One possible answer is that these structures, if not intelligently designed, and not dunes, were put there by stream mechanisms. Or the ridges and troughs - "ribs" as some call them - were carved by erosion that came from above. If that is the case, they would be more like gullies. Look closely at the image above (not its invert) and you can see where that higher section with the "rib" (or dune) shapes on it looks like it is on the verge of sliding away from the rest of the land. Some might say that this is a tube or tunnel that hasn't been exposed. Nevertheless, the process happening here is mechanical erosion, or mass wasting.


What other people are saying

NONCONFORMITY:

Ron Nicks, consulting geologist of The Enterprise Mission suggests one tenative answer is that these structures are part of a nonconformity. I suppose one could look at it that way. They certainly do look like they are composed of different material than what is directly below them. A nonconformity is part of a group of terms called unconformities. Unconformity usually means a disruption in the normal sequence of deposition. It often involves some deformation of the land, uplift and/or subsidence, and erosion. It could also involve changing sea level, or changes in climate. For instance an area with very definite and regular seasonal deposition, such as a lake, experiences a sudden change in climate. The deposition will change accordingly. Or perhaps a particularly disastrous flood completely carries away a section of previously deposited material, thus breaking up the regular sequence of deposition. Or there my be a period of no deposition at all. But if there is a pretty regular stratigraphic record, a geologist will know something happened out of the ordinary.

Nonconformity also means the coming together of two different material types, as Mr. Nicks said. This is usually sedimentary strata above and non stratified igneous or metamorphic rocks below. The structures could be resting on igneous rock, or some other harder, older substance. And the polygonal terrain certainly suggests some kind of movement. But this does not necessarily mean it is a nonconformity.

Both igneous and metamorphic rocks originate at depth. When the rock is uplifted, it may become exposed at the surface where weathering and erosion takes place. If subsidence occurs and there is water or other mechanical means, deposition will follow. A nonconformity is where the igneous or metamorphic rock and the overlying sedimentary layers meet.

This is something to think about. The "tubes" could be the beginning depositional layers of a nonconformity. But we just don't know until we go there and look closely at the stratigraphy. Perhaps it is some other unconformity.

Below are examples of unconformities. Do the tubes fit any of these scenarios?

The
first image shows an angular unconformity. Sedimentary rock is always laid down horizontally. Crustal movements - tectonic forces - cause deformation of the layers. Tilted or folded strata exposed to the elements will undergo weathering and erosion until buried. When deposition resumes horizontal layering will also resume. An angular unconformity is deformed sedimentary rock overlain by younger horizontal layers.

The
next image is a nonconformity. As stated above a nonconformity is where igneous or metamorphic rock meet sedimentary rock. Rock that is not sedimentary is igneous or metamorphic. Igneous rock is volcanic. Basically, metamorphic rock comes from pre-existing rock. Great pressure and high temperatures produce the chemical and structural changes necessary to transform the rock. For instance, under the right conditions limestone, deposited in layers, changes into unstratified marble. When tectonic actions bring these rocks to the surface, sedimentary strata may, over time, cover them. I made the top layer represent ripples, dunes or ridges and troughs - or perhaps the tube structures on Mars.

The
last image shows two disconformities. A disconformity is where erosion has taken away some or all of a section of strata. In a sense they are an absence in the geological record. But they are also a record of erosional events. The brown ripple like layers represent deposition of stream or windblown sand. Another substance covered them and preserved their form. Perhaps this is what will happen to the "Ribs" of the Mars "tunnels". Another layer of sediment could preserve them. Or erosional forces could completely wash them away, and deposit them elsewhere.

All the above unconformities together


Another unconformity is called a discontinuity. This means an interruption in sedimentation.

This is a typical deposition sequence. In this example let it be deposition in a fairly calm body of water - a lake. There are no disruptions in the layers - no tilting or folding. Stratigraphy starts at the bottom, with the oldest and first material deposited, and goes up to the youngest layer.
There are three distinct layers. Each layer has a different texture and grain size. For instance, the tan layer could be a sandy material. The next layer could be a finer grain, and the darkest layer a very fine grain material. The heavier sediment falls out of suspension before the finer lighter grains.
The sequence represents the activity on land. The sediment comes into the basin over a period of time. Perhaps annual rains wash it from nearby hills. Each sequence represents a year.
A: Normal, regular deposition.
B: Something happens - an earthquake, a landslide, man has moved into the area. This introduces new material into the sequence. If it is heavy enough it will deform the uppermost layers. This is an interruption of regular deposition.
C: Things return to normal. Regular depositional sequence resumes.
D: A slight change. There is less of the darker deposit. Something is different. Perhaps there was a drought, making transport of Sediment less efficient.
E: The darker layer is missing from the sequence. Clearly the environment has undergone change.
F: The two finer grained layers are completely missing. This is an discontinuity, a complete interruption in the sequence of deposition.
G: Renewed deposition of one of the other materials.


FAULTING:

Ron Nicks says the canyon might be "a structural feature related to faulting". Some people are calling these deep openings canyons. This is polygonal terrain. Granted they are giant polygons, but I wonder if canyon is the correct term. I have been calling them fissures and crevasses as well as canyons. Polygons form from freezing and thawing, and the land deforms accordingly. This is a big area. There are "worm/tubes" all over the place. When trying to come up with an answer one must consider the entire region. So there could be some kind of faulting happening here as well.

Fissures could form from Mars quakes. There would be uplift as well, making room for the nonconformity idea. Parts of the area look as if they are about to break open. Is this faulting or is this freeze thaw action? Polygonal terrain most commonly forms from freezing and thawing, forces that can be as powerful as faulting. What could cause such rapid and destructive freeze thaw action? Possibly volcanic eruption, or an impact event could. Permafrost might melt rapidly, and then refreeze just as quickly. Maybe this region was heavily glaciated at one time. Rapidly melting glaciers and permafrost would totally devastate the land.

Massive freeze thaw action is one possible history. Currently there could well be seasonal freezing and thawing, with streams of moving slush. This might account for those ribbed tubular structures. They could be something like point bar stream deposition. But nothing like the point bars we have along side our rivers and streams. These could be deposits of some strange new Martian polygonal geology.

We need more images. We need to catch it in the act - like those mysterious Martian dust devils that seem to get the blame for everything now. This is one of the pitfalls of finding something new on Mars. Suddenly everything fits the new scenario. But everything is not made by dust devils. Every hole or depression is not necessarily an impact crater or a graben. And every light and every shadow is not a trick.


Earlier I suggested that this might be glacial terrain. And that some of these "tubes" might be kames or kame terraces. I said that some of the craters might be kettles. There are a few things in this area that resemble glacial features. However, there are a lot of things missing from this scenario. The kettles might be large potholes, formed from small sections of permafrost or ice lenses. This is another planet after all. Mars could have some other way of making a kame terrace. Perhaps glacial processes on Mars are not exactly like those on Earth. Maybe Mars glaciers do not produce deep fjords, and U shaped valleys with their massive end moraines and braided streams. Perhaps giant polygonal landscapes are typical of Martian glacial processes.

That said, there are examples of tube shapes all over Mars - in different regions. No explanation seems to satisfy them all.

Making a Kame Terrace on Earth


Deposition from the mountains accumulates on valley floor. As the glacier advances it scrapes material from the floor and sides of the valley - pushing, shoving, plucking and scouring the rocks, and generally reshaping the landscape.


Similarly, a very thick icy stream, and/or one with a lot of rock and sediment could cause considerable erosion in a smaller chasm or fissure. A stream resulting from the processes of polygon formation, thawing at certain times and alternately refreezing would push against other surfaces. This stream could contain ice or ice mixed with debris. One way or another, when it freezes it puts a lot of pressure on the channel walls that hold it.



As the glacier grows and advances it shoves material ahead of it, and pushes against what it does not carry away. The rock and rubble in front of a glacier is called the end moraine. The land below and at its sides is under tremendous pressure.




Likewise, a heavily loaded stream will carve out the sides and bottoms of their channels and transport materials to other locations.


Glacial streams carry incredible amounts of sediment. Their size and force varies with the seasons, and amount of water and sediment coming from the glacier. A lateral moraine forms along the side the valley. It is commonly composed of loose rock fragments that get transported by the glacier, or rocks that have fallen from the adjacent slopes. Like stream terraces, sometimes there is more than one lateral moraine, depending on the height and volume of a glacier at any particular time.


In this image the stream has undercut the side of the valley. The original deposition from the mountain is rather hardened and compressed from the pressure of the glacier. But at the same time the ice-free land is rebounding.




With the pressure gone and the stream further weakening the structure, collapse is emminent.


Under similar circumstances, such as the release of pressure from any means (water could do it), the walls and margins of polygon fissures on Mars would suffer the same kinds of slumping sliding and collapse.







The intention of these drawings is to show the reader how some geologic process work. They are very basic, but hopefully my artwork makes them more interesting than graphs and charts. In real life things get much more complicated. Stratigraphy is not always so straightforward. Also, things may work differently on anther planet.

So far I have asked if glacial mechanisms might have formed these giant polygons. And I have looked at nonconformities, which could exist in any terrain. Nonconformities involve stratigraphy. Stratigraphy, the study of rock strata, embodies many aspects of geology and all forms of rock. There isn't much involving the earth that can be done - mining, tunneling, bridge building, the Arecibo Telescope - without some knowledge of stratigraphy.

Continued on Page 5


page 3 -- page 2 -- page 1


-- Credits --

Steve Wingate of Anomalous Images and UFO Files
Richard Hoagland, Ron Nicks of Enterprise Mission