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.

There are some who call it . . . Ross.

Dan:

Interesting article on research at Homestake mine which mentions both Ross and Yates.

Well if they are naming features after gold mines I hope they name something after my favorite, California's Empire Mine, being inspected here by Doug in 2009.

Enchanting, EG, simply enchanting...

I was thinking more along the lines of


wa-wa wa-wa-wa...


--Bill

OT, but love the shot of Doug...looks like he was gonna tear you a new one if you dared to try to push him in!!!

Back to Mars, we've shifted a bit - perhaps we're now looking at our next target, Deadwood:
http://qt.exploratorium.edu/mars/opportuni...0M1.JPG?sol2769
I don't see any veins here - perhaps they want to characterize the rock surrounding the veins?

So, I take it that the naming convention for now is "things in the Black Hills of SD"? I was stationed in the area in my younger days.

...and next we could do

Now somewhere in the black mountain hills of Dakota
There lived a young boy named Rocky Raccoon

and the whole White Album...



But seriously, @Fredk: "I don't see any veins here - perhaps they want to characterize the rock surrounding the veins?" I think that the light, broad areas are merged or consolidated veins and represent a more massive deposit of the Mystery Mineral. I'd be inclined to go over, inspect, RAT a nice flat spot and zing the chemistry for a few Sols. That would give the most return with the weak MB. If it is in fact a carbonate, it will be soft (Moh 3-4, about liek the siliceous Kieserite), so it would be an easy grind. IDing that mineral is pivotal. And yes, characterizing the surrounding rock (called country rock or wall rock) is needed.

I wish we'd thwack Homestake on the way out... I ~think I see rhombohedral cleavage in some of the fragments, which is very diagnostic.

--Bill

It's also possible that Oppy's left wheels rolled over Homestake in the sol 2769 move. Her left rear wheel is currently close to Homestake, perhaps even on top of it.

Sol 2769 Homestake my3D stereo pairs

Sol 2769 colour portrait of Homestake...

Click to view attachment

...and a 3D view...

Click to view attachment

To my non-geologist eyes the surface layout looks pretty helter-skelter around here. Yeah, let's hope they have the time for some more IDD'ing.

Homestake Sol2769

brought in the ultraviolet (L7)

Click to view attachment

Very much a psychedelic work in progress - and still playing with vector maths - here's a brief aside from the geology:

This is my take on Martian total diurnal insolation, for all latitudes throughout the Martian year.

White is maximum insolation. Green is 2/3rds of that. Cyan 1/2th, blue 1/3rd, magenta 1/6th. Low levels of light in the red zones turn to black: total darkness.

Got a solar powered rover? 4 to 5 degrees north appears to be the sweet latitude for you.

Andy

Another take on Homestake in 3D:

Click to view attachment

That's one of the things that I love about Midnight Mars Browser. Where else can one get such up to date information about the daily escapades of a robotic geologist on Mars.

If the theme is to be mineral veins and/or locales, I humbly nominate "Butte" for the next one after Deadwood.

"Deadwood"... I think..?

Click to view attachment

Yes, that's what it's labelled.

Thanks for the effort but your result seems counterintuitive, with maximum insolation occuring in the south polar region. Is the variable hours of sunlight, total energy received on a horizontal surface, or something else?

Steve M

I'll will check this (I have a raised eyebrow too!) but the midsummer southern hemisphere is just after perihelion - and that max insolation period is brief. What I think is happening is that, for a few weeks, the Solsworth of lowish-angle sunshine does surpass the incident energy of your average tropical day (which naturally is bracketed with your average tropical night).

Andy

My take on 'deadwood'. I tried some of the auto-flare removal improvements and other minor stuff... colors are bluer/whiter due to me driving the UV filter (for internal debug reasons)

Click to view attachment

Well...I think it was named after Ross the renowned scientist.

The intent of stopping at Deadwood is to characterize the rock through which Homestake apparently cuts. Squyres, Arvidson and company are very adamant about this piece of data to juxtapose with the content of the Homestake APXS data. The science team doesn't seem to think they -- Homestake and Deadwood -- are the same material at all.

As for RAT'ing or MB: only in our dreams. Long story short, we took a week-long detour that we expected to take only a few sols. The area ended up being so interesting to the science team that they convinced us to delay the trek. We need to boogey north on the double, because we only have so many sols to map the north-facing slopes and find our lily pads. Anything else scientifically intense will have to wait until after winter solstice (March 31).

There is, by the way a truly fascinating story to tell here about the pushback between science and engineering that has gone down over the last several weeks. The lesson of it all is that it has been an extremely productive week for the entire team. There are many considerations to evaluate when saying "we have x sols until we run out of time." It was questionable to take this detour given our need to rush north before certain things outside the control of the project take over and screw us, for lack of a better description. I would like to talk about a lot of these things in a blog post, but I need to wait until a) there's a press release on the Homestake content (hint: there'll be a press release soon!), since this is absolutely crucial to the discussion of tactical tradeoffs, and clear it with the project, since it would start peeling the paint off the proverbial privileged-information laws! So much cool stuff to talk about, so little room to do it right. (Hats off to the JPL media relations folks to, for keeping me steered on the right path!)

In any case, let me tell ya: it's been one hell of a week. The days I've been on tactical, I come home exhausted but enormously satisfied. We're really pulling off some magic -- not in sequencing complexity but in teamwork and engineering balancing acts. And the findings at Homestake are... well, pretty cool. Stay tuned. I'm signing off before I get any more proud and before I scoop the press release...

-m

Without giving anything away Matt, are we talking about conclusions based on camera filters and visible spectrum? Because as far as I can tell that's the only instrument that has been used on Homestake.

Thanks Matt!! I really love your input here so don't say anything that would end up gagging you!

Nope. From the latest update:

That became quite evident once we got Pancams of the spot-- the reddish tone of Deadwood make it appear light in unfiltered Haz- and Navcams. It is important to examine the Driftwood site, which apparently is an impactite/paleosoil that has been cooked and altered by the evident hydrothermal fluids of the Homestake veins.

What we see here are the age-old push-pull between exploration and production. Ah, to be a fly on the wall at these planning meetings. I'm thinking that "adamant" may well be an understatement.

Good info, and much appreciated.

Yawwwnn, no 00:35 imagery, maybe we'll get some later this AM...

--Bill

No, mostly APXS. But the Pancams also have a lot to say about Homestake...

-m

EDIT:



Don't hold your breath. Yestersol's plan contained... well, just about nothing (in the way of science). Not even a Tau, as far as I remember.

Today's planning will be busier -- drive+imaging in the queue, coming down sometime tomorrow morning.

-m

Indeed, this sure sounds like lots of APXS:


http://marsrovers.nasa.gov/mission/status_...rtunityAll.html

In that case I guess I can contaminate this thread a bit with yet another image of Deadwood.

Today's 12:35 Exploratorium update (the date counter on the Index page is still on 09-Nov-11, BTW) has several MI's from Sol-2771 (apparently Deadwood, p2996) and a 3x1 Pancam set looking westwardly from Sol-2772 of a target enticingly named "contact" (p2424) and Nav- and Haz-cams of unknown content.

Go fetch. They look interesting.

--Bill

Oh alright...

I think it's the "Contact" between CY and the surrounding plain...

Click to view attachment

... and a rather stylised MI view of "Deadwood"...

Click to view attachment

High-tailing it to the northern slopes again! Sol 2773 has this image.

Thanks Stu, et all, for the fine image processing of the last few weeks!

I'd like to second that emotion, The MI assemblies of late have been particularly well crafted...

Well that's a let-down. So much for my anticipation of shoreline features. No oyster shells or sand dollars. Not even a rusty set of car keys.

From above it does indeed look very like a shoreline, yet it isn't level. Could its formation nevertheless have something in common with that of a shoreline? A shoreline is produced by wave action, an agent that operates in one plane. Hence we find wave-cut platforms, cliffs, caves and so on within a narrow elevation range. Let's imagine a process that is confined to a surface, but one that doesn't have to be perfectly level. Erosion by saltating sand grains comes to mind. It would be localised near the curved surface of draped sediments surrounding protruding features, in this case dipping inward towards the centre of Endeavour.

So, is this 'beach' a saltating sand-cut platform carved out of Endeavour rim materials? I think the answer may already be on the way.

And the P2576 Pancam sequence (and associated Navcams) show the disturbed and disrupted Homstake vein in full glory...

--Bill

Oh my god, they killed Homestake...!!!

Click to view attachment

...and... look at that...

Click to view attachment

...and rough 3D...

http://twitpic.com/7dmg5a

I rotated the sol 2769 overhead pancam of Homestake and juxtaposed it with the sol 2773 pancam to facilitate comparisons. The sol 2769 overhead view (before disturbance) is on top, and the oblique view from sol 2773 (after disturbance) is below. Both images are raw, false color composites.
Click to view attachment

Oppy's a heavy girl... :

-m

...Hmmmm.

Sure seems like the white stuff is a lot more mechanically robust than the surrounding material. That is quite interesting indeed.

Indeed.

Purportedly, we intended to drive over it 3 times -- turn, turn, drive away. Not sure if we hit it all three times.

-m