Exploring Mt Sharp north of the dunes - Part 1: Beyond Pahrump Hills, Site 45-50, Sol 923-1147, March 12-October 28, 2015 Options

[neo56]

Here is my take on stitching pictures of this amazing place.
Sol 924:


Sol 925:




Sol 926:

[tdemko]

The shape, orientation, and geometry of these fractures reminds me of terrestrial examples of seal failures due to hydrofracturing via overpressure. This is also supported by the observations that they occur in a rather thick massive to laminated mudstone interval and terminate in the overlying more permeable coarser-grained strata.

For the interested, this a nice accessible review article on the subject:

Effects of mechanical layering on hydrofracture emplacement and fluid transport in reservoirs

For those less curious, here is a link to a nice photo from the article of the phenomena:

Hydrofractured Mercia Mudstone

For those in the UK, the classic exposures at Kilve and Watchet in Somerset are worth a pilgrimage to see these phenomena in incredible beach cliff and wave-cut terrace exposures. Check a tide chart, if you do though!

[jvandriel]

Here is the complete Navcam L panoramic view taken on Sol 926.

Jan van Driel

[jvandriel]

Wheeltracks on Sol 928.

Jan van Driel

[jvandriel]

MAHLI Panorama on Sol 930.

Jan van Driel

[Ron Hobbs]

What a beautiful rock!!!

[Phil Stooke]

Jan's full panorama in circular format.

Phil

[eliBonora]

Sol 930, some processing:




and anaglyph

[serpens]

Outstanding work Elizabeth.

[PaulH51]

The Garden City mineral veins, rotated and shown in context



Links :-
Large 1024 (1024 x 423)
Large 1600 (1600 x 661)
Large 2048 (2048 x 846)
Original (6985 x 2887)

Edit: Apologies, posted to wrong section, can mods please relocate the post?

[Gerald]

Sol 930 Right Mastcam image of a dump pile, probably of the Telegraph Peak drill powder.
This simplifies arm movements, e.g. for MAHLI wheel imaging, and opens an option for a next drilling.

With respect to the Garden City MAHLIs, here an annotated crop of this Sol 930 MAHLI:

With an interpretation of the darker phase as partially brecciated mudrock, having lithified a little faster than the light-toned fine-grained phase, I could get a more or less consistent view of the image. Both phases look rather resistant to erosion by considering the angularity of the surface; the darker phase maybe a little more resistant than the light-toned phase. Each of the two presumed phases may vary a bit in composition.

The part which doesn't like to fit easily into this interpretation are the parallel-looking features I've annotated by green lines.

Initially I've been looking for cleavages to narrow down mineralogy, but instead found these linear structures, which don't seem to care too much about the remaining structuring of the rock.

[neo56]

My take on MAHLI close-up on those mineral veins. Images are corrected from artifact and color corrected:

[tdemko]

The part which doesn't like to fit easily into this interpretation are the parallel-looking features I've annotated by green lines.

The features that Gerald has highlighted look like healed fractures; that is, fractures that formed by a propagating crack tip but were not subsequently propped open by fluid or precipitating mineralization. They would have closed, reversing the extensional, opening mode void. The cross-cutting relationships suggest that this was an earlier fracturing episode since they terminate against the mineralized fractures (veins). The fracture faces of these features seem to have been slightly mineralized (Gerald's parallel-looking features), making them a bit more resistant to erosion and stand out in relief.

[Gerald]

That sounds plausible. Thanks a lot for helping over this hurdle!

[Floyd]

Mars is full of serendipity. You spend 6 months throughly exploring and studying a scientifically important area (Pahrump Hills), then hit the road and travel less than 100m before finding Garden City.

To explore Mars with less chance of driving by unseen treasures (just 100m away behind a hill or in the next canyon over), it would be nice to have a swarm or rovers or a rover with a drone scout