[X] My Assistant

[Guest_AlexBlackwell_*]

Perron et al. have a new paper ("Evidence for an ancient martian ocean in the topography of deformed shorelines") in the June 14, 2007, issue Nature. There is also an accompanying News and Views piece by Maria Zuber. See the Editor's Summary for a synopsis and links.

See also:

Mystery Solved: Mars Had Large Oceans
By Dave Mosher, Space.com
posted: 13 June 2007
01:00 pm ET

[tglotch]

I don't know...Perron's a really smart guy, but I find the northern ocean hard to buy. I mean, I've stood out in the field in several places that geologists *know* were ancient shorelines, and they're really hard to see! And that is standing right on top of them and looking at aircraft imagery. Its an awful lot harder on Mars, especially when you consider the ~4Gy of deposition and erosion that must have occurred since then.

oops...~2Gy sounds about right..thanks dvandorn...but thats still a lot of time.

[Guest_AlexBlackwell_*]

I don't know...Perron's a really smart guy, but I find the northern ocean hard to buy.

I've closely followed Oceanus Borealis in the literature ever since Tim Parker published his first paper and really thought the data would confirm it. The initial MGS MOLA data (ca. 1998; published in Geophysical Research Letters) looked promising for Contact 2. After that, though, things went downhill. Carr and Head [2003] revived things a bit with a nice paper in JGR-Planets; see "Oceans on Mars: An assessment of the observational evidence and possible fate" (2.2 Mb PDF reprint).

In any event, I read the Perron et al. paper and found it really interesting. It does address one of the major obstacles about the current configuration and long wavelength structure of the putative contacts. Now if someone can write a similarly convincing paper explaining the lack of shoreline features in the hires imagery, then I'll be on the way to becoming a True Believer again.