QUESTION:
Hello, I just wanted to ask someone with formal scientific training about 
the so - called "pipes" showing up in many areas of Mars in the latest Malin 
"dump" of pictures. My first impression is that these "pipes" are naturally 
occurring, formed by a process roughly analogous to that of lava tubes 
formed by very low viscosity flows, draining through and leaving hollow tubes 
(typified by some Hawaaiin island flows). On Mars, perhaps the water is 
flowing from underground reservoirs to the surface, and then forming tubes 
with the walls formed of ice/ slush and dirt as the water hits the very cold, 
low atmospheric pressure conditions at the surface. The outer skin would 
freeze and stratify rapidly, forming bars or ribs, similar to those of a 
river bed, with regular spacing and variations in albedo/ reflectivity, not 
to mention translucensce in between the ribs -- leaving a pipe that probably 
freezes solid - or even continues to carry some liquid water. Why a tube?? It 
seems the most common structure in substances exposed to very cold 
temperatures when they flow through large amounts of dirt/ sand, etc. In 
that low gravity, who knows, such a formation could be very large. There are 
many other images that show similar structures, that are now flat, with no 
translucensce or pipe like curvature in "warmer" less water worn (appearing) 
areas of Mars, and they appear to be definite sand ridges of higher albedo .. 
implying these formations occurr, then eventually dessicate, or area wiped 
out by sandstorms or summer heating. Most of the pipes occurr in apparent 
water created crevices/ washed out areas at high latitudes ... exactly where 
such (hypothetical) formations would be most likely to occurr. Please forgive 
my theorizing --- my question is : Is this a likely possibility I've 
postulated?? Are there any plans to re - image these formations anytime soon 
with the highest possible resolution?? Any data/ theory developed to try and 
explain these highly unusual shapes? In case you haven't seen these "pipes", 
MO400291 at Malins website, taken from the MGS MOC camera in the Mare 
Acidalium region is a typical example. Thank You very much for your time/ 
consideration to what seems an interesting mystery -- R. Eikel

ANSWER from Jeff Plescia on August 8, 2000:

The features you describe and which have gotten a lot of attention are
considered to be formed in some sort of loose rock material.  They resemble
terrestrial channels form in sapping environments like the colorado plateau.  
There water comes out of permiable layers and runs down over the alluvium at 
the base of the scarp and forms a channel.

If I think I understand your idea, you are proposing that the features
observed are actually made of water ice and that the morphology is similar to 
that formed by lava.  In theory this might work. The problem is that ice is 
not stable on the martian surface at low latitude.  So even if you could make 
such a feature, the ice would rapidly evaporate and then nothing would be 
left.