On the Road Again - volume 3 - Page 4

sol 2034 ( Oct 14, 2009 ) L0 3x1 in next drive direction:

A backwards drive - 70+ meters??

Based on Tesheiner's UMSF sol 2034 map, Oppy moved NW - in the same direction as the large block in reply 40. My guess is that Oppy is a few meters to the north of the block.

Ah.

Here is one of the planned images on sol 2035:

02035 p2426.20 0 0 0 0 0 0 pancam_
">Mackinac_2x1_L256R2

The graphite inclsions have likely been ablated, eroded, or chemically processed away and may have resulted in the holes we see in the meteorites. It certainly could be a schreibersite inclusion pointing to the berry bowl. It's interesting that we have berries forming around meteorites that may have inclusions of schreibersite and carbon. schreibersite contains Phosphorus and graphite, carbon, both important in biological processes on Earth. Do they also act as fertilizer on Mars as well?
I wonder what kind of life likes Carbon, Iron, sulfer in a pooer oxygen and nitrogen environment...

Ug, I hate when I lose my post, I'll try again.
I wanted to restate this sentance:
Schreibersite contains Phosphorus and graphite, carbon, both important in biological processes on Earth.":

Schreibersite contains Phosphorus and iron- nickel. Schreibersite is rare in meteorites but it can be a minor source of phosphorus. graphite (carbon), and phosphorus are both important in biological processes on Earth.

rpage, you may be interested in this link.
[link]
The argument for meteorites doesn't necessarily follow as iron meteorites originated from asteroid cores. By inference it should also exist in planetary cores. As Earth has a collision with a Mars sized body, shedding lighter crust to form the moon, then there should have been lots of debris from the cores to provide phosphorus. Also plate tectonics should provide some replenishment over time.

sol 2035 (Oct 15, 2009 ) L2 2x1 of target "Mackinac"???:

er, what?

Probably just an error in camera pointing at the end of the drive. Wheel slippage or lack thereof resulting in a different waypoint that was anticipated?

sol 2036 ( Oct 16, 2009 ) 3D of Mackinac meteorite:

with a location link.

Looks like the "pointing error" in reply 67 was about 180 degrees.

I would be very surprised if this is not an iron-nickel meteorite of exactly the same composition as Block Island and Shelter Island.

sol 2034 ( Oct 14, 2009 ) L234567R1234567 of Shelter Island meteorite:

with links to two interesting areas - a patch of "white stuff" and "rusty edges?"

If the white stuff is not "just a specular reflection" ( which I doubt ) - then what is it?

If the reddish edges are in fact "rust" - then what does that imply about the local moisture conditions? Water a few meters below???

There's a new Planetary Society MER Update available:

[link]

There is almost no science content this time which I find disappointing.

There's this: Spirit is "still embedded in what turns out to be the edge of sand-filled crater west of Home Plate". What does that mean about the age and origin of the concentrated water-soluble chemicals that make up the deposit? Does this add any reliable constraints? I don't see how, as the filled crater could pre-date or post-date Home-plate.

There's this about Block Island: "Its size alone indicates that it hit the surface at a time when Mars' atmosphere was much denser." That appears to have been written before Shelter Island and Mackinac were found. I wonder if there is any way to distinguish air-burst fragments from spalled fragments after all the erosion? I don't think that anything really definite can yet be said about past atmospheric density. Beside the possibility of spalling creating the correlated fragments, there is no guarantee that the collision involved high relative velocities between Mars and the impactor or that the target material wasn't soft dust or ice at that time. Maybe all these other possibilities do not add up to much, but now with multiple "fragments" available there is a better chance of finding clear constraints on the impact event.

Hort., Regarding Reply 69:
It's gotta be an iron-nickle. I hope they image it further to examine the Crystal Cave in the lower center. There appear to be 2 crystals of iron-nickle oriented 90 degrees to eachother standing out in relief within a vug or cavity. Maybe they have a higher nickel content?

Regarding Reply 70: I dunno what the whilte stuff is? Maybe a sulphate salt.... maybe a phosphate/phosphide salt,... from reactions with the atmosphere. The "rust" looks to be mostly stuff from the wind, like magnetic stuff that stuck to the iron meteorite and rusted.

These meteorites represent a "sinkhole" for oxygen in Mars atmosphere. Oxygen reacts with the iron when it can, probably when atmospheric moisture condenses as water or ice or when oxygen becomes more concentrated. Atomic interactions on a micro-scale will cause iron and other metals to oxidize over vast time scales.

I think that the majority if the reddish irony stuff on these meteorites is fairly recent (within the past 100 millions years or more). I think that these meteorites have been on the surface for at least a few million years, maybe hundreds of millions of years.

If these iron meteorites were buried beneath the surface and interacted with ground water, the majority of any corrosion that might have formed on the surface of them would likely have been scoured off during the millions of years of exposure to the wind erosion of Mars.

These meteorites are mostly iron and a little nickel(Max nickel maybe 5% to 30%....I don't recall the exact%....... On Earth, I think it's 4 to 7% on average).

I think we are seeing how chunks of mostly iron meteorites are reacting with the martian atmosphere.

Earth iron meteorites have minor inclusions (a trace of well known elements and minerals). On Mars, these minor inclusions react with the atmosphere and available moisture over time.

These reactions occur in an arena that is a bit unfamiliar to us (The reactions occur on a smaller, more dominant molecular level AND over a much longer period of time).

I think that we certainly have enough information to decipher what the white material is. By looking at exposed metallic crystals in these meteorites we should be able to deduce how the Martian atmosphere reacts with elemental iron. It might not sound very interesting but learning how an atmosphere responds to elemental iron (and some of these well known trace components of iron-nickel meteorites) is actually HUGE!!!!!

sol 2037 ( Oct 17, 2009 ) L234567R1234567 of Mackinac meteorite:

Notice again that most of the voids are near the bottom of the meteorite.

Hort said, “Notice again that most of the voids are near the bottom of the meteorite.”

Hort would say, “Er, there is more humidity there. ”

I see what you mean Hort.
There is surely more humidity at the bottom there, I wonder what the heck the underside of that thing looks like!
I see what looks like a pyramid or two in the uppermost large void. Widmanstatten crystals are actually pyramidal (Octahedreal). Maybe this/these are widmanstatten crystals.

There are a few areas that look like they might be small clusters of slightly brighter metallic crystals richer in nickel that are more resistant to chemical erosion.

Hopefully they will take a closer look at that other even brighter stuff that looks like a water solubile white crystalline material.
It's very interesting to see an iron meteorite weathering away without lots of oxygen like we have on Earth.

I think I will stick with schreibersite and an acidic water table. I don't follow the humidity comment unless this was a few billion years in the past?

sol 2038 ( Oct 18, 2009 ) L0 3x1 after backwards 70 meter drive:

Looks like Oppy is back in the drive, drive, drive mode.

Although all of these meteorites are large enough to have created substantial craters, no evidence of such is visible .

Does this mean that their craters have been removed by erosion and the meteorites now rest at a lower stratigrapic level or could they be lower velocity secondary ejecta caused by the impact-disintergration of a large meteorite which created one of the big, nearby craters?
Doesn't their appearance and distribution suggest the latter?

IMO I believe the erosion surfaces of the meteorites is caused by differences in mineralogy and thearied reaction to the chemical environment in which they lay buried.
I think the red areas are fine dust and not "rust".

sol 2933 ( Oct 12, 2009 ) L234567R234567 infrared / visible detail of peculiar "berries" in / on Shelter Island:

The "berries" in the bowl seem to have originated from within the meteorite.

Note there is a small cluster of these peculiar berries on the outer surface also.

Usually "blueberries" appear "bluish" in L234567 false horticolor and "dark redish" in R234567satsqt infrared false horticolor.

These "berries" appear "bluish" in both visible and infrared.

What might they be???

As an aside, notice that the fine red dust appears very bright in the infrared.

Ben, the reason I think the "red tips" are "rust" and not dust is visible in this visible / infrared animation.

Dust in the image in visible / infrared is redish / whitish but the red tips are redish / bluish.

In fact you can almost "see" the "high water mark" on the sides of Shelter Island defined by the redish / bluish in the visible / infrared animation.