Journey to Mt Sharp - Part 5A: Pahrump Hills, Sites 42-45, Sol 753-923, Sep 18, 2014-March 12, 2015 Options

[anticitizen2]

Ok, the Hazcam mini-drill sequence is now down.

And here is a 2x zoom to watch moving regolith NB: 5.9mb

[neo56]

Nice animation anticitizen2 ! I'll certainly use them in my EPO talks to show drilling examples.

[wildespace]

3D anaglyph (for red/cyan glasses) of the mini-drill site: http://www.pictureshack.us/images/75085_MH756anaglyph.jpg
(the stereo has been adjusted so that the surface is level with your screen, and the drill tailings rise above it )

Interesting dark colour of the drill tailings. What could be said about the composition of rock, compared to the light-grey drill tailings in the past activities?

[Gerald]

...Interesting dark colour of the drill tailings. What could be said about the composition of rock, compared to the light-grey drill tailings in the past activities?

We perceive the brightness contrast between the original surface and the drill tailings. The original surface at Pahrump Hills looks brighter than than previous areas from HiRISE images. Taking this into account it isn't straightforward, that the absolute value of the albedo of the current drill tailings is lower than previous tailings.

If the surface and the tailings are made of the same material, it might just mean, that the tailings are rougher than the surface.

We may persue the reasons for the smooth surface at Pahrump Hills. One candidate will be polishing by nearby sand. But some properties of the rock will influence the result of presumed polishing, too. For instance, abrasive hardness should be rather homogenious above some scale. To be smoothed this way by sand, the overall abrasive hardness needs to be low enough; compare the sharp basaltic rocks, which are much less susceptible to abrasion.

If I interprete the drill tailings correctly, the presumed sandstone contains some clasts of a diameter of a little more than 1 mm. Assuming the previous reasoning as roughly correct, those clasts cannot be much harder than the finer grains or the matrix, almost ruling out, that they are made of basalt, but instead also of some sedimentary rock.

Further conclusions aren't really waterproof without further analysis, but a suggestive idea would be, that there has been a long sedimentary history of several generations of erosion and sedimentation, which finally transformed most/almost all of the original coarse basaltic material into soft sediments.
Back to the conclusions about composition: Long sedimentary history would drastically reduce original basaltic material like olivine and feldspar, and instead enrich quartz, clay, gypsum, might be carbonates, loads of possibilities. That's where CheMin will provide much more clarity, after preliminary LIBS and APXS analysis.

[Guest_Actionman_*]

Varying composition with clomping.

[anticitizen2]

Thanks, Thomas!

Mastcam before and after gives a good view of rock and sand movement

Mastcam Left

Mastcam Right

[jvandriel]

The Navcam L panoramic view on Sol 758.

Jan van Driel

[jvandriel]

and Sol 758 Navcam view in Stereo.

Jan van Driel

[jmknapp]

Nice vein through this one:

http://mars.jpl.nasa.gov/msl-raw-images/ms...697C00_DXXX.jpg

They surmised sulfate re Bonanza King.

Don't some of those features look like they flowed from a source rather than deposited?

[neo56]

I completed MC34 mosaic of sol 753 with pictures of sol 755:


Have you noticed dust shows different shades of brown on the rocky plates ? Probably due to different dust thickness...

[elakdawalla]

Moved several posts having to do with amazing MastCam images taken on the way to Pahrump Hills to the appropriate thread. Keep this thread for sols 753 and later, please!

[PaulH51]

We have a "full depth hole" on sol 759

This MAHLI tells the tale

http://mars.jpl.nasa.gov/msl-raw-images/ms...074R00_DXXX.jpg

[Y Bar Ranch]

We have a "full depth hole" on sol 759

This MAHLI tells the tale

http://mars.jpl.nasa.gov/msl-raw-images/ms...074R00_DXXX.jpg

Where's the grey material? Was kind of expecting it.

[djellison]

Where's the grey material? Was kind of expecting it.

Why? We're not in Yellowknife Bay / John Klein any more. We're in a different geological unit. That's kind of the point of driving all this way.

[Y Bar Ranch]

Why? We're not in Yellowknife Bay / John Klein any more. We're in a different geological unit. That's kind of the point of driving all this way.

Well, I'll flip my question around. Based on what they thought this unit might be composed of, do the tailings meet initial expectations or are they a surprise?