Just wondering, since Opportunity is quite near to these linear geologic formations, can we say that she has "very close veins?"

No, but one could say:

Abstract:
Rocks of the northwestern Sierra de San Andrés of the Vizcaino Peninsula of Baja California Sur, Mexico, form a partial, dismembered ophiolite sequence. Serpentinized harzburgite with minor dunite, orthopyroxenite, and pediform and disseminated chromite comprise the ultramafic section. Ultramafic rocks of cumulate origin are absent. An interior mélange of sheared serpentinite contains exotic blocks of altered serpentinite, metavolcanic, and metasedimentary rocks which range from greenschist to probable high-grade blueschist facies. A disrupted but intercalated section of layered clinopyroxene-plagioclase ± olivine cumulates and olivine melagabbro cumulates overlie the ultramafic rocks along low-angle faults. Orthopyroxene (bronzite) is the major intercumulate phase in the olivine melagabbro. Non-cumulate uralite gabbro is exposed in isolated fault blocks adjacent to the cumulate gabbro. Hornblende-bearing plagiogranite locally intrudes the uralite gabbro, resulting in an intrusive breccia. Plagiogranite with a diabasic texture composes another fault block which may be part of a sheeted dike or sill complex. At least 400 m of microporphyritic plagioclase ± clinopyroxene pillow lava is exposed. In addition, small scattered fault blocks of plagioclase ± clinopyroxene spilite and keratophyre may represent rocks derived from a deeper level in the complex. Pillow lava is conformably overlain by tuffaceous shale, friable Buchia piochi-bearing shale, potassium feldspar-poor volcanic arenite, conglomerate and pebblestone of the Upper Jurassic Eugenia Formation. The Turonian middle member of the Valle Formation overlies the ophiolite along low- to high-angle faults of small displacement. The ophiolite complex is cut by a west-trending shear zone and by northwest-trending faults. The latter are probably related to the Cenozoic right-lateral fault system of the northern Vizcaino Peninsula. Chemical analyses of ten gabbroic and volcanic rocks exhibit low K2O content and AFM trends characteristic of other ophiolites and abyssal tholeiite. This, together with stratigraphic evidence, suggests that the ophiolite is a piece of remnant oceanic crust which formed close to the Late Jurassic continental margin. It is suggested that prior to emplacement, the ophiolite formed the trenchward part of the upper plate of a Jurassic subduction zone. As a result of water derived from dehydration of the down-going oceanic crust, serpentinite diapirs formed in the mantle above the subducted plate and rose upward to a position below the overlying oceanic plate. The emplacement of the diapirs may have produced Cretaceous and Tertiary uplifting of the Vizcaino Peninsula.

http://sdsu-dspace.calstate.edu/handle/10211.10/201

about that photo I posted earlier and supppose that this spot on Mars has every bit as complex a history.

--Bill

I think so, with every Cape there's a Capillary

Found it!


Interesting series of 6 frames from the left and right pancams.
Wonder what the science was?

Good job!

I wondered the same thing, since we already have a full pancam series of all of homestake.

The small subframe images were taken interleaved with the larger Pancam set, in the same pointing. But I am clueless as to why.

Hmm. Now that you mention that, I remembered the Galileo SSI team used to do that sometimes. They'd return the whole image heftily compressed but sometimes resent back one small area of interest at much lower compression.

These were actually separate images, for each filter the tiny one taken just after the regular one, IIRC. But yeah, compression is the only thing that springs to mind? Or maybe some really obscure detail to do with the brightness of the subsection. Or something we haven't thought of.

Has it been determined that Homestake has been tipped by some process or (combination of processes) such that they are now standing like an underground stone fence?

Edit: voting for Northeast-facing winter parking spot, thinking of the winds flowing inside the big crater.

Ahh, well that's a big clue then. There were no pancams or navcams taken of homestake after the 2763 move until the full-view pancams and interleaved tiny subframes on 2765. Therefore they had no way of knowing where to crop the full frame images to get the tiny subframes perfectly centred on the vein of homestake!

So that suggests to me that this was a test of some method of figuring out how to crop on a target when "blind". One idea is that they built a model of the surface in front of them based on the images from the previous location or based on the front hazcam from after the 2763 drive, and used that to guess where to crop. Another idea is that they used some code to "find" a part of homestake to crop out, kind of like how they crop on the Sun. My guess is the latter.

Hi Brellis,

Crater formation is a chaotic process.

Endeavour is ancient and I have not found any good reference to its probable age.

But because of the clays and phyllosilicates seen from orbit ... it may have formed during an ancient wetter time or has seen water after formation. Homestake seems to be a 'possible' clay (like kaolin or smectite) or something else (see: Bill Harris' posts). Homestake's formation may have preceded or post-ceded (is that a word?) the crater's formation. BUT, the immediate edge of a crater 'usually' has deposits from the depths of the blasted material (see: E. Shoemaker's papers). After a billion years of events unknown and aeolian weathering, it is not very clear what this thing is. It probably came from underground and was folded up and over, during the formation of the crater rim. It is probably a fill crack precipitate that formed a long ago and we are at the right place at the right time as it has weathered to the surface. Oppy should run it over or whack it (after it has completed the preliminary study) to see if its just a small skinny crack-fill or a sheet...

All I can say is hold on and let the geologists and others scratch their way to a conclusion.

You and I live in fantastic times

I am no gelogist...rock types visible in endeavour crater rim would be expected to exhibit some water activity due to the energy involved in crater formation and not necessarily be indicative of a wetter ancient mars history??!

You might be right, based on the following commentary in an article about a suspected impact crater in Sweden:

www.geothermal-energy.org/pdf/IGAstandard/WGC/2005/0667.pdf

"After impact, much of the energy from the projectile has been turned into mechanical destruction and some energy remains in the form of impact melt rocks and their heated basement, especially in the central uplift region where previously deeper located rocks at higher temperature are brought closer to the surface (Melosh and Ivanov 1999). The impact structure will thus be a site for more or less extensive hydrothermal changes causing elements to dissolve and precipitate, depending on the local thermal gradients. (Puura and Plado 2004). The hydrothermal activity causes fracture filling where the most typical mineral in a crystalline environment is calcite."

RE: Dr.Howard's** post #388: "Sol 2767 fascinating area who's name we don't know yet..."

The mysterious Vein with No Name is now called... Ross.

--Bill





** as in "Calling Doctor Howard, Doctor Fine, Doctor Howard"

It's not Dr.; just Mike



Oh good; it was showing up as "Unexpected sequence" for me earlier today. Glad to know it has a real name; that stereo pair is one of my favorites.