Farewell Beacon..., The next cape beckons... Options

[Shaka]

Wow! If I live to be a hundred, I'll never understand why we've sailed right on past the Beacon toward "Boat Ramp". I agree that the deepest exposures are the most important, but Beacon is the highest! It's sitting right there waiting for us. It's the top of the section. Whether it's composed of impact breccia or undisturbed laminated evaporite determines whether Victoria formed after or before the deposition of the upper Planitia Meridiani. I can't believe that is a trivial issue. It is a fundamental fact of Victoria's history.

[CosmicRocker]

... But Tom, those of us in the "Ancient Victoria" school of thought, don't believe that we are seeing, driving over, or ratting Victoria's ejecta. We hold that ejecta is nowhere to be seen. What we are seeing is sandstone that roofed over Victoria back in the Noachian/Hesperian, was subsequently indurated and leached by ground water to produce concretions, and finally eroded and collapsed.

I am frantically awaiting close-up views of the uppermost exposures in the capes to see if they are primarily intact, in situ, more or less horizontal sandstones. The latest pancam of "Hoy" looks remarkably in situ right to the top. If close examination confirms this all around Vikky, then I will hold my hypothesis to be supported. I cannot emphasize too strongly that a hypervelocity impact shatters the target rocks near the crater, transforms some into exotic forms, hurls them high into the air and deposits them around the crater with a more or less random orientation of chunks (OK, clasts) in an impact breccia. We saw some of this around Beagle, though that was such a tiny crater that regular impact models may apply imperfectly.
I have not yet seen anything around Victoria that I would call impact breccia. Close-up views may reveal it, if we ever get any. Hence my disappointment when Beacon was bypassed. ...

But Shaka, I contend that we have seen several cross sections of capes relatively close-up at this point, including CSM. All of them appeared to be mantled by a jumbled layer of blocks in random orientations. That looks like an impact breccia to me. The stable places that have endured long periods of erosion seem to display flat faces eroded by wind, and the less stable areas that have seen mass wasting more recently display the boulders in various stages of erosion. I don't see anything like in-place bedding at the surface on any of the capes, so far.

I know that in the past I had argued that Victoria wasn't all that ancient, but I have since modified my view and have mentioned that. I think it is fairly old, but I am not certain how old. I am still looking for evidence of the hypothesized ancient fill that was eroded, undercut, and which subsequently collapsed. I am not convinced I see it in the close-ups we have so far. If I had to make a guess from our current selection of close-up samples, I'd guess the original crater was smaller than the current hole.

I agree with Phil's points. I think our position represents one pole of a "streak hypothesis", ...
We could call these two schools of thought, the "Clean Streakers" and the "Dirty Streakers"!
I'm sure Ustrax could devise some appropriate mascots.
Who wants to sign up?

I agree with him too, but...Oh, no. Let's not start another polarizing argument with team badges. We won't have the measurements needed to decide until Opportunity gets to a dark streak, and even then we won't have the calibrated spectral information. From my point of view, the simplest explanation is that the well observed and globally distributed light dust has been removed here, as it has on all of the rougher, upper slopes of this crater...