This ejecta apron, and the blueberries in general, are quite a conundrum, no?

Even though there was a tremendous amount of energy transferred to the bedrock by the impactor and most of the bedrock was pulverized there were undoubtedly "quiet" nodes of lower energy where the shock wave cancelled itself out. This is a classic problem in designing a shot to fracture rock in mining. Therefore you will find pieces of less-fragmented bedrock. And an impact crater like Emma Dean can bring these fragments to the surface.

The hershey's kisses are a mystery. I have problems with the venifact (aeolian erosion) idea but it does offer a good explanation of observation that the facets have a similar orientation, as do the kisses with the point=up. Spherules emplaced by the impact would be random.

We saw blueberries embedded in bedding surfaces at Eagle and Endurance and a couple of examples of this in the Cape Faraday rock.

I saw the "w"-object and wanted to see stereo pairs before mentioning it. Too, too odd.

This stop may be a delay in reaching the photo-op at Victoria but there is good science to be gained here.

--Bill

You don't mean that re: the depth, do you?

Very good job on the colorization from the uncalibrated stretched JPGs !
It almost looks like if it was one of the PDS-calibrated "true" color images
Also thanks for providing the formula (I'm surprised that a simple linear combination of the
filter channels already yields such "near-calibrated-looking" results since I once experimented with more complicated non-linear color mappings but with poorer results ...

Actually, I was suggesting that the smaller spherical objects we're seeing here in the annulus are *not* hematitic concretions, and thus are entirely different in morphology and composition from the blueberries we saw in Eagle, in Endurance and on the plains. In this hypothesis, of what we are seeing here in the soils of the annulus, only the bodies that have been modified into conical shapes would be concretions. The smaller spherical bodies, while they resemble mini-concretions, would be (I'm suggesting) impact melt droplets.

-the other Doug

I can see how some of the berries appear Hershey's kiss shaped, due to the brighter spot at top dead center, but I don't think they really are that shape. If the 3D images I posted were not convincing, then take a look at the shadows these things cast. The shadows should display a projection of the conical shape, if that is their true shape. Instead, the shadows display circular or eliptical shapes.

Look above to the false color pancam from sol 936 that Bill posted in message #92. It shows a good sampling of the spheroids in a wide range of sizes, and they all seem to be casting rounded shadows. They are all the same color and hue, suggesting that they are similar in composition, so it is hard for me to believe there is a sub-population of impact melt spheroids, even though I'd like to see some of those. I'm just not sure if much melt would even be created by an impact into rocks of this composition.

Looking at Emma Dean crater, we finally see just what one would expect if it was a hole punched into the ejecta blanket of Victoria...a jumble of lithologies, and nothing like Beagle and earlier craters. I am eager to move on to Victoria, as the rest of you are, but I really hope they move closer to this hole and take a closer look at it's walls. I'd really like to take a close look at a cross section through the ejecta. I'd also like to know if that is a piece of the Halfpipe formation right of center on the opposite side of Emma Dean. This is a pretty nice little crater. I wonder if Oppy will wander into it.

This comment reminds me very much of an exchange between Dave Scott, on the Moon, and Joe Allen, the CapCom back in Houston. It occurred just a few minutes after Scott and Irwin had discovered the "Genesis Rock," a piece of nearly pure plagioclase, at the rim of a small crater on the Appenine Front. Despite the excitement of the find, Allen was pressing the crew to move on to their next stop:

Scott: Hey, Joe, this crater is a gold mine!

Allen: And there might be diamonds in the next one, Dave.

So, yes -- Emma Dean may have some very good finds in it. But, as always, we have to remember that Victoria might have diamonds in it...

-the other Doug

The hershey's kisses aren't shaped exactly like our chocolate confection, the departure from spherical is very small. Physical and color differences are very subtle, but nonetheless present.

Unlike the carbon-based rovers in Apollo, the silicon-based rovers in MER are not on a tight time schedule for the traverse since they will run out of oxygen at a known point in time. Although unlike the Black Knight they are not invincible, the rovers are far from loonies. We ought to keep moving on because the clock is ticking but not at the cost of science. The diamonds at Victoria will be there in a few Sols more. Science as well as photo-ops.

--Bill

This is a bit off topic, but since this thread seems to have the attention of some of the geologizers, I hope it will be appreciated. I came across an abstract from last Spring's LPSC that I had somehow missed. RELATIVE AGES OF GEOMORPHIC FEATURES VISITED BY THE OPPORTUNITY ROVER.

This 2 page pdf should not be too large of a download for those on dialup, and it addresses several Meridiani observations that have resulted in many long-winded discussions here about things like ripples, cobbles, polygons, and mini-craters. I'd recommend this short paper to anyone interested in those topics. Anatolia is seen as a large scale version of volume-loss polygons observed on many scales. Mini-craters are viewed as either small craters or rimless pits...and more elongated sapping features are described as pit chains. I like the way this abstract condensed a huge amount of observations and interpretations into only 2 pages. There are a few more diamonds to be found in it.

It is almost an epiphany to read something that mirrors observations that you have had for a long time. I really need to spend more time reviewing the current literature. The previous post is in no way OT.

BTW, there is discussion about the ejecta apron and the Emma Dean roadcut in Squyres' current Mission Update at http://athena.cornell.edu/news/mubss/ .

--Bill

And mixed in with the initial Navcam views of Victoria's stratigraphy we have a couple of partial-frame Pancam sequences of selected Emma Dean features. L257's here, with interesting compositional changes.

--Bill

Yep, I noticed those too Bill... very interesting... I posted this over on another thread but I think it slipped past everyone...

Click to view attachment

And the one you pointed out...

Click to view attachment