Victoria's Innards, Your last chance to speculate before we really see it |
Victoria's Innards, Your last chance to speculate before we really see it |
Sep 25 2006, 04:41 AM
Post
#1
|
|
Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
So, here's a nice little short-term thread, to let people get on the record with their wild speculations as to what we'll see when we get "up close and personal" with Vickie.
Some have mentioned seeing gully-like features in the walls, in the MOC images. I'll take this moment to disagree -- it looks to me like the talus slope (which makes up most of the exposed interior of the crater, that and the dune field) is streaked all along the interior, and that some streaks swirl a bit as they approach the upper rim. I think what we're seeing here is mass-wasting down the slopes of a non-homogenous surface. While the bulk composition of the surface layer that's slowly falling into Vickie is probably all pretty similar, there are obviously pockets of lighter and darker materials. Those pockets are sliding down into the crater, leaving a striated look as light deposits slide down adjacent to darker ones. At this point, the wind circulation system within the crater kicks in, modifying the light and dark streaks -- especially near the upper rim around the capes and down into the bays. I think the gully-like feature leading down from Duck Bay is probably nothing more than a mass-wastage slide of dark material down into the crater that has been swirled up a bit near where the winds howl in through Duck Bay. Let's see, what other potentially embarrasing predictions can I make? I think that while the dark spots on the far rim's cape structures aren't entrances into deep caves, I'd bet that some of them are shallow "alcove" caves. Places where softer rock have been windblown out of the near-vertical rock face, leaving dimple-caves in the rock. While these would be great places to repel down into and set up a sleeping bag for the night (the cliffs keep the big predators away, after all... ), I doubt a MER would ever be able to make its way into one... -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
|
|
|
Sep 25 2006, 02:26 PM
Post
#2
|
|
Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
One of the puzzles to me is the scalloped rim of Victoria, which is unique but not too unusual. Looking at Slinted's meridiani_themis image, we see several degraded craters to the northeast and southeast that have a very soft rounded rim and a central dunefield and one crater with a hint of scallops. Only one, Victoria, has the pronounced scallops but I interpret the soft rims on the other craters as a scalloped rim in a late stage of development. And you recall that the Payson outcrop area and the so-called "Payson Promontory" may be a highly eroded bay-and-cape at Erebus crater. And we may have seen immature forms of the scallops at Endurance crater with some of the cliffs standing out from the receding pre-bay areas. I'm wondering "why?", and presume that this relates to the mechanical and structural properties of the evaporite unit in this locale as well as Martian weathering processes.
As an aside, the next Rover mission ought to start in Big Crater and work it's way NW toward Victoria; that would be a wonderful traverse. --Bill -------------------- |
|
|
Lo-Fi Version | Time is now: 25th June 2024 - 09:19 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |