After turning my head 90 degrees clockwise (ouch- my neck hurts- I should right-clicked save-as and then used photoshop...) to compensate for the pseudoscopic effect that was making me see craters as a domes, I understood the interpretation of the picture.
The upper left corner has some linear depressions that look like collapsed cave galleries (note- their widths should be around 100 m). One of these canyons is close to what looks like a large sinkhole, and may be connected to it by a non-collapsed gallery.
If its karst, the scale is enormous. The only similar thing I have ever seen is the Peruaçu canyon here in Brazil (cave ceiling may be up to 100m high). I know that in Asia there are galleries with larger volumes.
BTW, I belive they are using the term tectonic-controlled karst to indicate that the features (collapsed cave galleries) are controlled by tectonic sructures (fractures or fault zones).
The features were developed in what seems to be a mesa-like relief, formed by flat-lying layers (sedimentary or volcanic). Outcrops of these layers can be seen on the left part of the picture.
What's important here is the term "karst-like". Karstic landforms can form on a variety of rocks, like limestone and sandstone (as well as its metamorphic equivalents).
The key point is that these rocks need water to be formed (chemical and clastic deposition in a variety of environments), and karst morphology needs water to be generated. So, Mars must have had free water for time enough to:
(1) deposit these rocks
(2) allow for these rocks be uplifted
(3) allow formation of karst morphology
If the features are karstic, and if were generated by the same procceses that create them here on Earth, chances are that life may have had a bit more chances to appear and evolve. And also provide very interesting targets for exploration. A nice place also to look for life.
But let me also propose an alternative explanation- those layers may be basaltic lava flows, and the canyons may be collapsed lava tubes.
In any case, I would sell my soul to explore that place and do some research there. See? That's proof that there is no devil...
As for the dark areas disposed in vertical (in relation to the picture orientation) streaks, I would guess that they are areas where the wind swept away the upper layers of soil, exposing a darker substrate.
A crater located close to the centre of the picture but a bit to the top left shows a concentration of clear material close to its "lower" rim. It can be interpreted as material not removed by the wind, due to its location at the trailing edge of the crater (in respect to the prevailing winds, that should be- if this interpretation is correct, from the "top" to the "bottom" of the picture).
Regarding the greenish hues, I don't think thats clorophyl-bearing vegetation. I would guess its due to lightning, filters used, image proccessing or perhaps even some greenish mineral. If there are spectrometers (are there any?) in the orbiters, they would for sure detect water or carbon (well, I belive they would but I'm not sure, someone please correct me if I'm wrong).
Sorry for the long post...
