Venusian Channel Formation As A Subsurface Process Options

[Guest_AlexBlackwell_*]

There's a new and interesting preprint at JGR-Planets in Press:

Lang, Nicholas P.; Hansen, Vicki L. — January 2006
Venusian channel formation as a subsurface process
(2005JE002629)
PDF [8.7 Mb]

[elakdawalla]

Cool -- a paper that contradicts the assumption central to my Master's thesis

The observation central to this work is: there are lots of channels on Venus but if you look at the topography along them, they don't go from uphill to downhill; they undulate a lot. The assumption I used in my thesis was one first suggested by Goro Komatsu and Vic Baker: that the channels could be used as a marker of paleo-flatness, so you could learn something about what's happened in Venus tectonics since the channels formed by examining how topography along channels differs from flatness. This paper says, no, the channels formed that way, because they didn't form on the surface, they formed below the surface at the interface between the plains lavas and some other layer.

I'll be very curious to see if they present this at this year's Lunar and Planetary Science Conference and what the other people in the Venus community think about it. But it may be hard to get an unbiased opinion. Vicki Hansen (second author on this paper, the first author is very likely a Ph.D. student of hers) has long represented one polar extreme in an extremely, nastily polarized debate about how to interpret geology from Magellan SAR images; the other pole was occupied by my graduate advisor, Jim Head, and his coworker Alexander ("Sasha") Basilevsky. After witnessing one particularly ugly and non-constructive debate between these two poles at an LPSC meeting, one of my fellow students (Geoff Collins, now a professor at Wheaton) summed up their debate: "I feel like Sasha is arguing 'Can't you see the forests around you?' while Vicki is shouting 'No, no! There are only trees!'"

--Emily

[Guest_AlexBlackwell_*]

The observation central to this work is: there are lots of channels on Venus but if you look at the topography along them, they don't go from uphill to downhill; they undulate a lot.  The assumption I used in my thesis was one first suggested by Goro Komatsu and Vic Baker: that the channels could be used as a marker of paleo-flatness, so you could learn something about what's happened in Venus tectonics since the channels formed by examining how topography along channels differs from flatness.  This paper says, no, the channels formed that way, because they didn't form on the surface, they formed below the surface at the interface between the plains lavas and some other layer.

Although different mechanisms and processes are involved, there are interesting parallels with similar debates regarding Mars' ancient valley networks.

[elakdawalla]

Although different mechanisms and processes are involved, there are interesting parallels with similar debates regarding Mars' ancient valley networks.

Huh. I didn't know that -- do you mean that people are talking about a subsurface (or maybe subglacial) formation mechanism for the valley networks? I'd be shocked and amazed if Komatsu and Baker weren't also involved in these studies -- they've cornered the market on planetary channels.

--Emily

[Bob Shaw]

Huh.  I didn't know that -- do you mean that people are talking about a subsurface (or maybe subglacial) formation mechanism for the valley networks?  I'd be shocked and amazed if Komatsu and Baker weren't also involved in these studies -- they've cornered the market on planetary channels.

--Emily

Emily:

Well, Baker likes floods. Big floods. Reallllllly big floods!

So maybe sub-glacial channels wouldn't have the same, er, flush of enthusiasm...

Bob Shaw

(who *must* one day visit the scablands!)