Solander Point - Page 12

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hortonheardawho


Posts: xxx

Reply: 221



PostPosted: December 22, 2013 3:01 PM 

Kye, here are links to the original size illustrations of the Field Notes from Mars:

Opportunity_Climb_status

3519_HiRISE_setting

3512_Navmos_east

3512_Navmos_west

3518_dust_factor

Hope this helps you read the annotations.

I got the links by right mouse clicking on the images and selecting the "Inspect Element" operation and then examining the src field. You have to append the server domain name ( ie, http://www.nmnaturalhistory.org ) to the front.

newboy discussed how pre-impact rocks could end up on the rim in reply 117

I don't believe Endeavour is small enough for pre-impact rocks to "rebound" and fold back on the rim. I favor the view that everything on the rim is reworked breccia - so any clays found were created "in place" after the impact.

But I'm just a picture guy...

Kye Goodwin


Posts: 1166

Reply: 222



PostPosted: December 22, 2013 9:33 PM 

Horton, re your 221, Thanks for doing that. Now I can read all the annotations. I'm not sure whether I understand Crumpler or not. Referring to the 3rd illustration, the east panorama, an area is labelled "older, pre-impact rocks of interest" and another area across the contact is labelled "Impact breccias". Does he mean that the first area isn't breccia at all, that is, undisturbed bedrock; or does he mean that it's breccia that still has a preponderance of material from a particular pre-impact stratum "of interest"?

I've researched the ideas of "uplift", "rebound", "folding" and "inversion of strata". Here's my (unfortunately unreferenced) conclusions: During an impact bedrock does NOT distort like rubber and then snap back, though I've seen many secondary sources that state or imply this idea. Elastic rebound is not a significant part of the impact process. Rock can be distorted only very, very little before it fractures and the fracturing is irreversible. Rock acts like a fluid only if it has been broken into small vibrating pieces. Big solid blocks of bedrock can be spalled loose and flipped over at the edge of the transient cavity (top of the wall), and breccia can come to rest on the rim without being completely mixed, that is, it can retain some part of the separation of materials that was present as pre-impact strata, but extensive inverted bedrock is never the result in either case. There is "uplift" by which the bedrock rim of the crater rises slightly but otherwise stays in-place. I think that this effect results from the slightly greater volume of the underlying bedrock after impact fracturing. The depth of ejecta on a raised crater rim is usually far greater than the uplift component of the rise. Maybe I've got some of this wrong. I'll happily read any primary references that anyone wants to pass along.

We aren't very far up the Cape compared with the level of the surrounding plain, so I guess that we could still be at an elevation that was bedrock before the Endeavour impact. In that case the raised position of the capes would have to be partly illusion created by the erosion of the plain and rim, but that's not much of a problem. I have a serious problem with the Capes being a mixture of pre-impact bedrock and post-impact ejecta. The ejecta would have to be on top of the bedrock, not beside or below it.

hortonheardawho


Posts: xxx

Reply: 223



PostPosted: December 24, 2013 1:57 PM 

Merry Christmas from Oppy on Solander Point.

RJS


Posts: xxx

Reply: 224



PostPosted: December 25, 2013 12:05 AM 


Nice animation Hort! Merry Christmas to you and a very good night.

Kevin


Posts: xxx

Reply: 225



PostPosted: December 25, 2013 8:05 AM 

Ho ho ho Hort!!

Merry Christmas to and and all.

Barsoomer


Posts: 344

Reply: 226



PostPosted: December 25, 2013 12:45 PM 

Now if only we could get some Whos as a Christmas present!

hortonheardawho


Posts: xxx

Reply: 227



PostPosted: December 26, 2013 9:25 AM 

Sol 3524 ( Dec 22. 2013 ) enhanced difference false color panorama of Cook Haven:

Perhaps the clay is in the soil - not the rocks?

Perhaps the soil is wind blown clay dust from an ancient global storm that settled on the rim of Endeavour between rocks.

Perhaps. Perhaps. Perhaps.

Now, let's plop the APXS on the "reddest" soil and the "bluest" rock and see what's what.

Barsoomer


Posts: 344

Reply: 228



PostPosted: December 27, 2013 4:38 PM 

This is the first good image we have seen for some time of the former stain area. Unfortunately, it is a right eye only.

Barsoomer


Posts: 344

Reply: 229



PostPosted: December 27, 2013 4:45 PM 

Hmm. Notice the blob-like "corrosion" that was previously on the terminal lead area seems to have moved to the nearby screw area.

hortonheardawho


Posts: xxx

Reply: 230



PostPosted: December 28, 2013 9:48 AM 

Sol 3527 (Dec 26, 2013 ) false color panorama in the next drive direction:

The choice of a 5x0.5 L257R7 pan is unusual. Perhaps the team can't decide where to go next?

My "vote" from the back of the bus is the large light rock surrounded by smaller dark rocks about 30 meters south. ( between the first and second image in the pan )

Today's plan ( sol 3530 ) is more MIs.

Kye Goodwin


Posts: 1166

Reply: 231



PostPosted: December 29, 2013 5:31 PM 

Horton, re your 230, Thanks. I got excited when those large rocks first appeared in images a few days ago, but then I realized I had no idea how large they are. If they are 30 m away, then they probably are the largest rocks we have seen since starting the climb.

I think that one unexpected quality of the cape material in general is the small size of the breccia inclusions, or more that there is an upper limit on their size in a place where pieces up to the scale of enormous boulders would be normal. Another unexpected quality in the cape material is the high ratio of the volume of matrix fines to breccia inclusions, especially now with the discovery of the Cook Haven material, which seems to be much like the Burns Formation, a matrix of bright fines with spherule-sized inclusions. I think that the tall capes have a core of material that is truly ejecta still in-place from the Endeavour impact, but we haven't seen any of this yet. When we do, some of it will be in much larger pieces.

Aldebaran


Posts: xxx

Reply: 232



PostPosted: December 30, 2013 6:17 PM 

Opportunity will have been exploring the surface of Mars for 10 years as of next month. It has been a long time (also since I was last here).

Kye Goodwin


Posts: 1166

Reply: 233



PostPosted: December 31, 2013 11:50 AM 

Aldebaran, Great to hear from you! I hope you will stay around and get back into it. Oppy's presently less than 50 m from the the ANSWER, in my opinion.

hortonheardawho


Posts: xxx

Reply: 234



PostPosted: December 31, 2013 12:31 PM 

Sol 3528 (Dec 27, 2013 ) false color 3D of rover deck on Cook Haven:

I haven't been able to check earlier views of this area to see if the "stuff" is recent. The disk drive which contained ALL of my older Mars pictures crashed a few days ago and I have been unable to recover it so far. The BIOS in THREE computers no longer recognizes the drive.

It sucks to get old.

Speaking of old...

Sol 3509 (Dec 7, 2013 ) false color panorama of Cook Haven:

Maybe Oppy should park in this area for a few weeks and hope for a "cleaning event"?

Kye Goodwin


Posts: 1166

Reply: 235



PostPosted: December 31, 2013 12:53 PM 

Just looking at the most recent traverse map I can make a case for the east slope of the cape including material unlike what we've seen along the west side and Murray Ridge.

[link]

Some of the east slope looks bouldery, especially further south where isolated boulders appear to have moved downslope. We haven't seen any large rocks up close on or near the cape that appear to be comprised of the whole rock, that is matrix and inclusions. The material of Solander that we have seen so far has little tendency to erode to boulders. Add this observation to the large basalt rocks examined at the edge of Solander Point, which appeared to the rover team to have come from a collection of rocks upslope, and we've got pretty good evidence that the core of this cape is something other than the relatively fine-grained breccias observed so far.

Aldebaran


Posts: xxx

Reply: 236



PostPosted: December 31, 2013 10:32 PM 

"Aldebaran, Great to hear from you! I hope you will stay around and get back into it. Oppy's presently less than 50 m from the the ANSWER, in my opinion."

You mean the phyllosilicates/ smectites, I take it?

Aldebaran


Posts: xxx

Reply: 237



PostPosted: December 31, 2013 10:47 PM 

My hunch is that we're dealing with mylonites or phyllonites to be specific, probably rich in Fe and Mg chlorites. In other words, I think we're dealing with shear zone minerals. Let's see if that hunch is right. The APXS should be able to tell.

dx


Posts: 1661

Reply: 238



PostPosted: December 31, 2013 11:59 PM 

Aldebaran>>>

You remain in Australia with your new Prius or reworking your 'short wave' radios?

yt
dx
Very Happy Wink

Aldebaran


Posts: xxx

Reply: 239



PostPosted: January 1, 2014 3:25 AM 

Hi dx,

I'm still in the same place in Australia, but haven't driven a Prius in about 5 years. It served its purpose well. Currently drive a 4x4 SUV since I do a lot more fishing and less long distance driving. I could also walk to work if I wanted to for the next year. After that, it will require a boat trip.

Kye Goodwin


Posts: 1166

Reply: 240



PostPosted: January 1, 2014 1:31 PM 

Aldebaran, re your 236 and 237, It sounds like you have been following Oppy all along, or at least got back into it recently, so I won't try to fill you in on what's happened over the 5 years that you've been gone.

I'm not excited about the clay minerals because I think that we have already found clay in the bright Meridiani rock generally, 10% nontronite :

http://www.lpi.usra.edu/meetings/lpsc2006/pdf/2021.pdf

The images mapping the orbital detections of clay minerals on the capes also show less intense detections of clay in patches on the surrounding bright rock:

http://www.planetary.brown.edu/pdfs/3954.pdf

I don't think the clay will tell us much until the bigger picture is resolved, and I don't think it will be illuminated much by spending a month examining Cook Haven, any more than Whitewater Lake on Cape York resolved anything. Whitewater Lake is in my opinion a distal impact sediment. That is also the first hypothesis of the rover team in this paper, though they list other possibilities. See the final section:

http://www.lpi.usra.edu/meetings/lpsc2013/pdf/2352.pdf

Cook Haven is also a distal impact sediment, in this case draped over the real proximal ejecta of Endeavour Crater, which includes a lot of basalt boulders like the rocks encountered at the base of the east slope where Oppy first approached Solander.

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