The fellow whose site you linked is not someone whose work I am familiar with, so I’m going by the work I am familiar with. While there is certainly room for disagreement among scientists, my personal opinion is that the liquid water theory best fits the evidence that we see on Mars’ surface. The question of where the water came from and where it went is still an open one, as I noted before. Current conditions on the surface of Mars are definitely not conducive to the existence of liquid water but we still have much to learn about the history of the planet, and again, I think the evidence for rivers and lakes having existed in the past is quite strong. I honestly have a hard time with clouds of gas and dust having created such a floodplain, particularly having transported boulders of such large size.
I dunno. I’ve seen an avalanche of snow carry massive trees along. Why couldn’t an avalanche of dust/sand carry rocks?
(I’m not trying to be contrarian here, Geobabe. Like I said, just playing Devil’s advocate. Personally, I hope the water explanation proves to be correct.)
Along a steep slope, certainly, avalanches can carry extremely large objects, but the area where Pathfinder landed was not steep but rather flat. This is why it is frequently referred to as a floodplain, since that is what it most closely resembles: a large, flat or very gently sloping area. There is a steeper area some distance away, but an avalanche expends its energy very quickly once it reaches the flat.
This has actually motivated me to delve into the literature a bit, so the followup questions are proving to be a good thing.
You should come over to my house sometime, spoke-. Mars is one of my favorite topics, and I have several books on it, including a big National Geographic hardcover compiling most of the Viking and Pathfinder photos and a bunch of pics from the early days of the Mars Global Surveyor mission. I also have a globe of Mars.
The stratification IIRC, is seen in the banks of putative river channels, strongly implying that an ancient lake or ocean laid the sediments and a later river then cut through them. I’ll try to find a link with pictures tomorrow when I’m at work and have T1 (and am supposed to be working, sshh).
That Mars has a large inventory of H2O isn’t aggressively disputed; most of it is probably now in the poles and in subsurface permafrost (My Natl. Geo. book has a good photo of a “splosh” crater: the ejecta surrounding the crater is in the form of rounded lobes, as if the heat of the impact turned tons and tons of hydrated permafrost into mud, which splashed out all around.).
The better question is how that H20 could have existed in liquid form for millions of years early in the history of the planet, as the evidence tends to say it did. Not only is Mars about 150% farther from the Sun than the Earth, but the Sun was much cooler back then too. It’s very puzzling.
Maybe the answer is in areothermal heating. Or maybe the greenhouse effect was more successful than we think it could have been. We really need to go there if we want to find out for sure.