Any geothermal activity?

Been lurking for awhile. The recent comments about ammonia on mars and it either being biology or volcanic has got me thinking.

Compared to earth, what percentage of geothermal activity can exist on mars?

Even if it's smaller with less radiological decay to generate internal heat, i would think realisticaly Mars ought to have .5-2% of earth's heat output.

there ought to be small earthquakes and volcanic eruptions every decade or so, paticularly over tharsis, and some hints of at least fumeroles or a few signs of underground heating of water.

I'm a broken record on this, but Opp showed an inside-crater temperature of 40F. Outside temp of -60F.

I can't think of anything that explains that swing but hot springs or geothermals.

You'd think Andrew that that alone would drive NASA to check out the dunes in the bottom of the crater. I've been a broken record on that.

We need answers.

Is Mars active?

Some of the atmospheric gasses can reslt from either geologivc activity or organic activity.

Thus far there is very little evidence of organic activity, particularly of a scale to acount for those gasses, so it seems appropriate to deduce that their concentrations are at least contributed to by geologivc sources.

It seems highly unlikely that Mars is "dead". Solar tidal forces alone should generate enough heat to maintain at least a minimal level of geothermal activity.

Surely thermal radiation from the planet has been measured. That would in itself indicate whether or not the planet "lives"

Since water shrinks when it melts, and there is supposidly lots of places on mars with a high concentration of ice in permafrost, i wondered if there is any evidence of sinkholes or slumping.

I don't think Endurance crater is volcanic,but am curious about the heat difference and i saw what looked like sinkholes around the rim.

The other phenomenon that can cleave the N triple bond is lightning. There is a good theoretical basis for electrical discharges on Mars, although it has not yet been observed. On Earth, lightning produces NOx and NH3, and even HCN. On Mars we have many more free radicles in the atmosphere due to the lack of a geomagnetic field and the consequent influx of ionized particles.

There is currently research being carried out on electrical discharges on Mars. Guess who's doing this research - That's right - NASA.

To blandly say that the only possible explanations are volcanism and biology is PUSILLANIMOUS ! NASA. I can't believe how these guys can bow to political pressure like that.

Thank you Aldebaran!

any others?

The question is not whether Mars generates heat from radioactive decay- it undoubtedly does generate some heat this way. The question is whether that heat can be conducted to the surface and lost as heat radiation without melting or convection.

Earth is too large- too thick, with too low a surface area to volume ratio- to permit conduction alone to release all the heat generated internally. As a result, we see convection (as expressed in plate tectonics) and melting (as expressed in volcanic and intrusive igneous rocks)on this planet.

Mars is probably small enough to allow internal heat to merely conduct to the surface and escape. Whether heat flow alone will suffice is not too hard to calculate, but it's been 20 years or more since I went over the formula in a geophysics class. I just don't remember it. You also have to have some estimate of the internal heat generated, and I don't know if there is such an estimate for Mars.

As always, I have tried to qualify what I'm saying. I don't think anyone is claiming to know for sure that Mars is volcanically and tectonically dead- but it does seem likely that activity is very rare. I for one think that warm water convection in the crust is quite possible, an excellent habitat for life, and could help explain many of the anomalies we are observing. However, if this circulation is at significant depth, there may not be any recognizable surface expression such as warm spots or springs, fumeroles, geysers and so on. Gasses could slowly diffuse upward and escape over a large area- "vents" as such might not exist.

I read a while back that "mysterious" flashes of light have been observed on Mars.

It occured to me that su;ch could resut from lightning. Not generated as we are accustomed to, but rather by blowing dust.

blowing dry dust can gnerate one heckuva static charge, so it seems possible that such a charge might be generated and than flash over to an area of opposite charge. I know its possible, but can only guess if it happens.

I didnt know planets could so easily dispose of heat just by conduction. I always thought rock makes for a good insulator.

I thought maybe cause the crust of mars is so much thicker, magma under mars can only conduct heat through weak spots, to residual heat would tend to form permanent hot spots, that's why the tharsis bulge is well a bulge, I thought it's a huge tounge of mars mantle flowing upward.

mcooney- The calculations I referred to yesterday involve a number of assumptions- the amount of heat generated in a planet and the types, distributions, and thermal conductivity of rock. For earth, we can make some very good guesses, and have a fair degree of confidence in their accuracy. If we assume Mars is similar in most ways other than volume, it should be able to loose most or all of its internal heat through conduction. This presumption is supported by the lack of a magnetic field- which suggests that there's no molten core. The Tharsis bulge, in this case, would be a rememnant of Mars' earlier volcanic/tectonic activity.

However, in the absence of strong data, there is still a possibility that assuming similar natures between Mars and Earth is a mistake. I have read a number of articles in the past few years discussing circumstantial evidence that Mars may have had active volcanism in the not-too-distant past. Nothing convincing, except in convincing me to keep an open mind. The best way to put it is that our given our current understanding, it seems unlikely Mars is active. But our current understanding is not as firmly rooted in hard data as we would like it to be to draw firm, final conclusions.

BTW, rock in great thickness is a good insulator, but even the best insulator is not perfect. That is the root of the calculation- look at thermal conductivity and distance, and figure out what the heat gradient from inside to outside would be. If the inside ends up hotter than melting temperature- which we know pretty well- then melting and convection take over. If equilibrium temp is below melting, conduction will dominate. Note that "melting temperature" is pretty darned hot- in the neighborhood of 1200 degrees C and up depending on pressure. The interior of Mars is almost certainly hot, just not enough to melt. This is why the idea of water circulating in deep fractures is very compelling to me.

In reply 5, mcoony asks:

i wondered if there is any evidence of sinkholes or slumping?

The answer is yes, lots of evidence. Go to the MOC page and search "sinkholes"--there are over a doen good images of large Martian sinkholes, both singly and in chains, that are NOT impact features. Some of these seem to show clear fluid alteration.

Of course, there are also at this point many hundreds of pictures of gullies on crater walls. Penny Boston has published several papers theorizing that there are warm "microenvironments" on Mars associated with both natural geothermal activity (to a small degree), and imapct sites (to a large degree). The temporary energy from a big impact can trigger local geothermal heating that lasts 10,000 years or longer, melting ground ice creating karst-like cave and sinkhole formation, not only in the crater, but impact fissures radiating from the crater, sometimes over long distances. These new caves themselves become heat sinks that may last long after the primary geothermal energy has subsided.

Boston may get to test her theories, as she is currently on development teams for two different possible future missions. She also has a nice website on "Caves of Mars" (sorry, don't have URL handy).

Good thread, btw, mcoont--glad you stopped lurking. ALthough I mostly lurk myself, and can't even do much of that during the summer.

since the humidy is 100percent.
and the pressure so low that water at the bottom of the crater is attempting evaperate but cant thus generating heat?
(dont worry its not scientific just thinking out loud)

please forgive my ignorance. ok mars shows signs of past volcano activity and canyons possibly carved from running water. this implies to me that at some point the geothermic activity on mars was enough to force the water to the surface. at some point the core cooled or the tectonics settled to the point where there was a equilibrium between heat generation and dissipation.

based on those assumptions i have a few questions. is it possible that a large impact to the surface of mars ( ie meteor or comet) could shift the tectonic plates enough to force renewed geothermal escape to bring water to the surface again?

is it possible that earth might undergo in time the same settling that would allow the water to seep into the ground leaving it dry on the surface?

is it possible that without an "earth killing" impact, earth (or mars), would settle into a dormant phase until the next impact revitalized it into and active, life supporting environment.

so basically my little brain storm is this. given time, mars (and maybe some day earth) has settled to the point where the water has seeped away from the surface of the planet. will it remain that way until there is some outside factor forcing it churn water to the surface and therefore creating a environment that we consider supportive to life?