A question here, behaviour of water on Mars Options

[spdf]

A question here

There are signs that in the past there was liquid water on Mars. So lets assume thats true.
Since the gravity on Mars is much lower than on Earth, so how does water (waves) behave on Mars compared to Earth?
Someone did say, that waves would have been much higher but also much slower. Is this true? Does anyone have an animation where you can see a waive on Earth in comparsion to a wave on Mars?

Thanks

[Juramike]

Space.com article says that the crust of Mars is colder (and thicker) than previously thought.

From the article:

"Unexpectedly, the radar scans also revealed the massive weight of the ice cap does not deform any underlying sediment. This implies the crust beneath the cap is strong — more than 180 miles thick (300 km).

To have such a thick crust, "Mars might be colder than we thought," Phillips told SPACE.com. As a result, any liquid water that might be underground has to be buried even deeper than once speculated. "If one thought that liquid water was 5 kilometers deep (3 miles), it's now at least 30 percent deeper than that," he said."

(The article to be published in the May 15 issue of Science is not yet available.)


I have a really ignorant question, here: What is the ductile strength of sediment with interstitial ice? Is it stronger or weaker than normal sediment?

-Mike

[dburt]

Space.com article says that the crust of Mars is colder (and thicker) than previously thought.

From the article:

"Unexpectedly, the radar scans also revealed the massive weight of the ice cap does not deform any underlying sediment. This implies the crust beneath the cap is strong — more than 180 miles thick (300 km).
..."

I have a really ignorant question, here: What is the ductile strength of sediment with interstitial ice? Is it stronger or weaker than normal sediment?

Mike - So here's an ignorant answer. If by "normal sediment" you mean unconsolidated sediment (i.e., loose particles) where the pore space is filled with liquid water (below the water table) or air (above the water table), presumably ice-cemented sediment should be somewhat stronger, because ice is a solid. However, ice expands as it freezes, and can move sedimentary particles around (e.g., in ice polygons inferred on the Martian surface), so that ice-cemented sediment could be weaker than an actual sedimentary rock (if the particles in the rock were cemented by something stronger than ice).

That ambiguous answer may be irrelevant, though, because the space.com quote appears to be inadvertently misleading. They are not really talking about deformation of a thin, weak sedimentary veneer, but about deformation of the much stronger and thicker underlying igneous (metamorphic?) crust and uppermost olivine-rich mantle (i.e., what geophysicists call the lithosphere on Earth). The colder the underlying solid rock, the less easily deformable it is. So what they are mainly saying, if I am guessing correctly, is simply that Mars is somewhat more rigid (and therefore colder by inference) inside than was formerly modeled (at least beneath the poles). Calling this cold, rigid layer "the crust" appears to be PR-speak for "cold and rigid lithosphere". The present-day lack of plate tectonics on Mars (i.e., the fact that Mars is a one-plate planet) already implies that Mars has a very thick, rigid, non-deformable lithosphere. The lack of deformation owing to the weight of polar ice caps strengthens (pardon the double-entendre) this inference. Again, just my ignorant answer - I'm not a geophysicist and haven't read more than what you quoted. (I do know enough to state that a seismic network on Mars could provide badly-needed data about the martian interior.) Hope this clarifies rather than confuses.

-- HDP Don

[dvandorn]

...I do know enough to state that a seismic network on Mars could provide badly-needed data about the martian interior...

Oh, we are *so* in agreement! If there are two sets of data I dearly want from Mars, one is from a sustained seismic network, and the other is from a carefully designed heat flow network.

Those two sets of data could seriously constrain a lot of the current theories of Martian history, IMHO.

-the other Doug