And here is the color views


The anaglyph (dedicated to Stu )


And a closer view with the mosaic :


For sure, a very beautiful rock! Very close to HSR.

Ant, what can I say but WOW!!!! Fantastic, absolutely gorgeous!

I'm especially intrigued by that sort of crystalline-looking structure just above & to the slight right of the big hole...a sharp metal shard?

EDIT: Ant, I defaced your beautiful work in MS Paint to add a circle around the feature I was referring to.

Awesome imagery, Ant103. Thanks.


The first thing that comes to my mind would be a survey of the meteorite's surfaces, studying the three dimensional distribution of blueberries and other sediments in its hollows.

Looking at the distribution of berries apparent in the latest imagery, it seems that the largest berries have collected in the lowest hollow, with smaller concretions at slightly higher elevations. There are very few, if any, visible in the highest hollows. We can't yet see into the hollows around the sides of the meteorite. I can think of several ways to interpret the available observations.

Beautiful! I'm struck by the contrast between the smoothly rounded left (leeward?) side of the rock and the rougher, pitted, right (windward?) side, indicating that even metal can be eroded by wind-driven grains on Mars. The raised rims around a couple of the "vesicles" inside the big pit are also interesting- do they indicate that the "vesicles" are intrinsic structures and not just erosional features?

John

Block Island Ramblings...
Well, Block Island seems to be significantly metallic, with possible stony inclusions (I'm basing this on appearance). The many vesicles seem to be gas bubbles from the ancient solidification, although some of them could be from inclusions that have since evaporated/dissolved/eroded away. The raised rims around some of the vesicles indicates something inside the vesicles reacted with the structure of the meteorite and made that surface slightly more resistant to erosion.
The vesicles could have been refilled for a time after the meteorite fell, with ice, Meridiani sulfur-salt goo, dust, or whatever.
The elaborate filigree structure around the big pit indicates a hard material with tensile strength (metallic), and it looks like it is being slowly eaten away chemically. The filigree structure could also represent a fine-grained soft component in the metallic matrix that is being preferentially eroded.
Looking forward to microscopic images.
The presence of 'blueberries' in the hollows could be remnants of previous burial, and/or wind-driven deposits from an episode where Mars had more atmosphere.
There we go, enough opinionated ramblings to power Oppy for a day, at least!

-- MarkG

Block Island seems to be sitting on the flat, rocky layer of Meridiani like it was just placed there. If BI at some point had been buried in layers since eroded away, I would expect to see it either sitting in a depression or up on a pedestal. On the other hand, I don't see how it could drop on the surface as it is with no sign of an impact mark.

No depression or pedestal to indicate layers being eroded from around BI, no sign of an impact on the current surface....
I'm confused.

Couldn't they be regmaglypts that have been subsequently enhanced by eolian erosion?

If BI has been eroded by chemical means, is that not something of a confirmation of a highly acidic water table in the area (admittedly, long ago)?

-the other Doug

Would a big dune be enough to damp the impact before it touched the bedrock? I imagine that, even if the bedrock was damaged, as long as the meteorite was embedded above it, a seasonal water table could have erased the crater before Meridiani dried, the dune was blown away and the meteorite was left on top.

Stu, thanks for the great review of Rover meteorite finds. And no wonder you're the poet laureate -- from the Lake Country!

SFJCody, in line with your thought on regmaglypts enhanced by aeolian erosion, and extending the same idea to John_S's windward and leeward sides, I am imaging that I can see remnants of an orientation -- bleeding edge on the right -- as Block Island roared through the Martian atmosphere.

Another truly remarkable find by Opportunity! Who would have predicted that it would find, not one, but two picture-perfect iron-nickle meteorites (if that proves to be the case) on the surface of Meridiani?

BI is very cool...but now we're here I'm waiting for "the other reason"

What about the meteorites that they find in the Antarctic? Don't they frequently find ones just sitting on the surface, with no impact crater? Are there similar aeolian erosion and ice sublimation processes at work over a prolonged period?

You might be. I'm not. You're miss-interpreting Tim, as I explained earlier.

Ilbasso,
Antarctic meteorites mostly represent lag deposits left behind by melting and evaporation of the ice cap they were previously embedded in. They got into the ice after entering the atmosphere, which slowed them to terminal velocity - from maybe 12 kilometers per second down to only 0.1 km/s, more or less. They hit the ice cap or snow without enough energy to make a proper crater or significantly damage themselves. Subsequent snows buried them in the cap and they rode it as far as the dry valleys or other erosion zones where they were lag deposited centuries/millenia later.

It would be premature to postulate a similar ice cap deposition and concentration mechanism for Meridiani, but Block Island need not be sitting on the same surface it originally hit. Erosion could have removed that ages ago. Still, if Oppy had the ability, it would be fascinating to turn BI over and closely examine the bottom and the underlying bedrock for scars of impact.

Thanks Ant, great work! I missed the new BI pics coming in "live" 'cos we were away camping, again, but back now and having fun with them. This is my fave rock for yonks, and not just 'cos I was getting stir crazy looking at mile after mile of undulating dust ripples... :-)



And amazing structure in the "hollow"...