Hello Nick -

Interesting discussion, much of it simply beyond me - why are CL, Br, and S indicators of volcanic processes? Are they by-products from the deterioration of heavier elements?

Oh well - I don't think any here know much about the Hausteca, Olomeis, and Totonacs, and certainly not enough to differentiate them.

The sulfuric acid was from an analysis by Sagan. I think that a video of his Mars analysis which he presented to the Association of Space Explorers should be out there somewhere. NASA would do far better in remembering him if they remembered his planetary science instead of simply naming a lander after him. Perhaps NASA management could put the History Office on to the task of locating the video and making it more widely available. If not NASA, maybe Cornell.

I've already pointed out what I thought to be water trickling from some impact craters on Mars. As I thought that perhaps Mars could be terraformed by impactor diversion, I am reluctant to face up to this, but perhaps what is released instead of water is sulfuric acid. If sulfuric acid is released, terraforming becomes impossible, and manned exploration becomes even far far more difficult than was earlier thought. Truly a dismal conclusion, and a dismal end to a grand dream.

I think you need to re-examine your analysis of CO2 content of the Martian "magma" - the clathrates. What we can see in the canyon walls are regular strata - this has to be a regular periodic process. To my thinking these regular strata indicate uniform periodic releases of volatiles by cometary impact. Their regular periodicity is explained by Clube and Napier's cometary injection hypothesis: as our solar systems passes through the plane of our galaxy, the Milky Way, which occurs regularly every 26 million years or so, the gravitational effects are enough to dislodge comets. These hit Mars and release volatiles.

Perhaps the split nature of the current sample being examined on Mars preserves evidence of one of these regular events, instead of relating to formative eventgs.

As I mentioned before, you can count these strata on exposed valley walls, multiply by 26 million, and come to an estimate for the time of the end of watery Mars.

On Earth, impact may be implicated in volcanism - the impactors actually punching through the crust down to the Earth's molten magma.

I don't think mankind would survive an impact of this magnitude.

On Mars, we're also seeing small strata in local "wind" derived deposits. Something must be binding the tops of these strata - care to guess what that binding agent might be? (oh boy, even more "good news" - ughh)

As for timing geology on Mars, I don't know how European crater counting efforts are going, but I hope that they're going better than the ones here. Last time I checked, Chapman's team had hit real limits, as they lacked the necessary expertise in image processing, which is only available at MIT, Carnegie Mellon, and a few other places.

I also do not know about the sensitivity of the spectra on Mars Express. There will be multiple passes and data integration, so resolution will improve.

oh well - carry on -
by 2007 we'll have the Cassini images - 2 and half years or so. Maybe the ESA or NASA crater counting efforts will be on track by then.

ep