A closer look at "Sputnik" crater by Opportunity?

In this thread on bautforum.com I speculated the feature called "Sputnik" crater might be a volcanic vent:

A volcanic fissure at Victoria crater?
http://bautforum.com/showpost.php?p=852014&postcount=39

It's the roundish feature below and to the left of the "Duck Bay" label in these annotated Hirise images:

Opportunity is headed back to Duck Bay as a possible entry point into Victoria crater. Perhaps the rover could take a look at Sputnik first before entering Victoria.

Bob Clark

Hi Bob Clark.. Thanks for the link. I found it interesting.

Maybe the answer to my questions were in the link and I failed to see it. If Opportunity can get close enough to Sputnik, might there be clues as to how long ago it was active and how old Victoria is? Or does that require a humand hands-on investgation?

Thanks, RJS

Which of these two edges is the upper left edge of the crater? What "standard" impact crater has two rims?

Cropped PANCAM image showing Sputnik crater.

You see there is barely visible a raised rim around the perimeter of the feature but the double edges at the upper left are exaggerated in size compared to the rest of the rim.
I found something analogous to this in regards to volcanic vents in this online lecture:

Pyroclastic Landforms and Pyroclasts.
http://skilling.geology.pitt.edu/GEO3975/pyroclastics/pyroclastics2.pdf

As shown in the image on p. 8 of this lecture, a blown up edge could be due to wind driven ash from the vent:

"Diamond Head near Honolulu is a famously difficult phreatomagmatic landform to slot into ring vs cone. Most of edifice resembles a tuff ring, but wind has given rise to a steep cone-like side. Most of deposits are also typical of tuff cones rather than rings. Hence several factors control ring vs cone (hydrology, wind, efficiency of magma-waterexplosions etc)."
PyroclasticLandforms and Pyroclasts, p. 8.

But what's really key in this lecture is discussion of the fact that volcanic vents can have nested rims. See page 9 with an image of Hanauma Bay, a nested tuff ring complex on the coast of Oahu and page 14 with "Asymmetric nested tuff cones of Koko Crater on Oahu".

Some more examples of "nested" volcanic craters:

Santa Ana Volcano.
"The summit of Santa Ana features four nested calderas and volcanic craters, with the innermost containing a small crater lake."
http://en.wikipedia.org/wiki/Ilamatepec

Santa Ana Volcano, El Salvador.
"The volcano sports several crescent-like craters—“nested” craters—at its summit and a 20-kilometer-long system of fissures."
http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17054

This might be an especially relevant analog since it has a larger volcanic crater nearby the nested crater that has a scalloped rim. This would be analogous to the Victoria scenario if Victoria is a volcanic collapse feature as I suggested.

Also:

Ibu, Halmahera, Indonesia.
"The nested sumit craters of Mt. Ibu. A brand new lava dome can be seen within the central crater, emitting a plume of volcanic gases."
[link]

Global Volcanism Program | Volcanoes of the World | Types and Processes Gallery | Craters.
Cotopaxi.
"The glacier-capped summit of Ecuador's Cotopaxi volcano is truncated by two nested craters. The outer crater, seen here from the SE, is 800 x 550 m wide. A cone that grew inside this crater is cut by a smaller crater that is 250 m wide and 120 m deep."
http://www.volcano.si.edu/world/tpgallery.cfm?category=Craters

Harrat Hutaymah, Saudi Arabia (Page 2 of 2).
"Looking northwest to the nested cinder and spatter cones of Harrat ad Dakhana in the north-central part of the Harrat Hutaymah volcanic field. Photo by Carl Thornber, U.S. Geological Survey."
[link]

Bob Clark

Robert, is this the same crater that Ben used to say looked like a volcano?

Your image in Reply 1 won’t work for me.

Can you post a NASA/JPL or Exploratorium image of this Sputnik Crater?

Thanks, Henry

Henry & Bob : No, I have always advocated it is an impact crater that has been modified to appear as it now does.

We have seen no evidence of volcanic material around this part of VC and there is no indication of late, volcanic activity in Meridiani.
Bob if you want to see some of the volcanic features you mention, go to Columbia Hills and I will show you a bunch of them .

Ben,

Start a tour. We would all love to see. Dont know much about rocks. I think I would be a good thread with great intrest.

Darwin

I believe Sputnik Crater is the hole on the right hand side of this image.

Henry, I posted that image of Sputnik on site Bautforum.com, as well as the other images I cited from the "Pyroclastic Landforms and Pyroclasts" report. The link for the image was to that site but apparently you have to have that site open to view the image.
You'll have to register with the site if you're not already a member to view them:

Sputnik crater as a volcanic vent.
http://bautforum.com/showpost.php?p=1020731&postcount=436

The Sputnik image is taken from this Hirise image of the Opportunity route:

Opportunity Route Map.
http://www.unmannedspaceflight.com/index.php?act=Attach&type=post&id=10866

Bob Clark

Double-click on the space above where the thumbnail SHOULD be.

Odd. Here's another image of Victoria in which Sputnik doesn't appear to have the "double edge". What's more it also seems to have the classic "bowl" shape of impact craters:

You may need to rotate the image to get it to show the correct relief.

The image comes from this page:

Spirit Detours in Silica Valley, Opportunity Returns to Duck Bay to Enter Victoria.
By A.J.S. Rayl
June 30, 2007
[link]

We'll get a better look when the image is released at the highest Hirise resolution.

Bob Clark

.........yea,

Dont mess withe me.

Darwin

Excuse post 10, that was an IM to a friend.
I put it in the wrong box.

This is an interesting feature. Would be nice to get a close look before oppy puts on the bandana.

Darwin

Bob; it looks like the double rim you see is probably due to dune material that has blown in the small Sputnik crater.

You may be right Ben. But it is puzzling why that second rim is not visible in the the newest Hirise image of Victoria, though admittedly we can't be sure of that until the full resolution image is released.
What also struck me originally as strange about Sputnik was that it looked "filled in". That is, it had a flat bottom in the earlier HIrise image. It didn't have the usual bowl shape for an impact crater:

But now in the latest Hirise image it looks like it does have the bowl shape.
Could the difference just be because of a different filter used for the two images?

Bob Clark

The full resolution version of the new Victoria image has been released:

HiRISE | Opportunity Rover Tracks at Victoria Crater (PSP_004289_1780).
http://hirise.lpl.arizona.edu/PSP_004289_1780

The second rim is still not visible. I attached a cropped portion of the full image, zoomed in on Sputnik. I rotated it 90 degrees clockwise to make it clearer it's a depression in the ground.
I don't know why Sputnik looks so different in the two Hirise images. It's not the filter used since they were both taken with the red filter.

Bob Clark

That image didn't attach.
Here it is again: