[X] My Assistant

[elakdawalla]

Thought I'd start a new topic for the HiRISE images of the Viking 1 and 2 landers:

Viking 1
Viking 2

--Emily

[Ant103]

Here is a more color-realistic view based on the hirise picture (1,1 Mo)

[dvandorn]

Here is a more color-realistic view based on the hirise picture (1,1 Mo)

Wow! This view of the landscape is absolutely incredible. I've run out of superlatives -- I'm reminded of John Young, standing on the Moon, using the word 'spectacular' for the fourth time in five minutes, and then apologizing, saying you just run out of words...

From a geologic point of view, this image shows quite well that the boulder populations are concentrated on the floors and rims of depressions, but with a strong bias towards the west-northwest inner rims and east-southeast outer ramparts. This seems to match one of the two predominant sets of lineations; one set runs nearly horizontal through the scene, dipping only slightly to the south as it moves to the east, and seems to be composed mostly of dune, ripple and other aeolian features. The other set, which seems to align with the positioning bias of the boulder population, runs from east-southeast to west-northwest. (*) These lineations are rougher and expressed in larger features, the apparent sculpting of what now looks like a "scoured" terrain that, prior to the scouring event(s), featured a lot of 10- to 20-m craters.

Seeing as how the Chryse region was selected as a landing site because it's located in the midst of an apparent ancient catastrophic outflow channel, I guess you'd expect to see signs of directional scouring in the basic landforms. It looks to me like many of the boulders were deposited preferentially in the "downstream" sides of craters.

This image is, to me, far more compelling evidence of ancient catastrophic floods in the region than anything we actually saw from the surface.

* - All of the above directions assume that north is up in the image; I'm using them relative to this image only, and don't intend to convey that north is indeed straight up throughout the image.

-the other Doug