Large fractures (to be differentiated from the small polygonal fracturation) Long/lat: (no particular order) E, 23.84N E, 23.85N E, 23.83N E, 23.92N E, 24.07N E, 24.02N E, 24.12N Rational: Fractures are a particular place for potential fluid circulation. It would be of utmost interest to study the material filling the fractures, for different habitability conditions than the rest of the clay unit. The objective will not be to drive to all of them, but to target the closest to the actual landing site, and possibly some other(s) on the way to other targets. Morphology & mineralogy: Large fractures are present on every red outcrop of the Fe/Mg-clays. However, they are particularly larger and denser in the areas shown here, near the boundary with the upper Al-clays. MSL tasks: At large scale, study the relation of this features to upper and lower layers, the possibility of variations between the center and external parts of the fractures. At small scale, the grain structure, the mineralogy and chemistry of the rocks, in the different levees, and in different parts of the levees HRSC mosaic with HRSC nadir & color images 7

We see here the transition from fracture filled by dark sand to levees formed by differential erosion. 1 1 km HiRISE mosaic with HiRISE color images Increase of erosion Inversion of the fracture

We see here concentric fractures (only example on the landing site). 5 km HiRISE mosaic 2

We see here « multi- fractures », fractures that go parallel, very close to each other. 100 m HiRISE mosaic 3 « Multi-fracture »

4 This area is characterised by short, non linear fractures (see close-ups in next slides) Next slide After next slide HiRISE mosaic with HiRISE color images

200 m HiRISE mosaic Some fractures look similar to dunes. In some cases, it is almost impossible to distinguish (question mark). Some of the dunes are shown by the red arrows, but most of the features in this image are fractures (except in upper right). Most fractures are surrounded by a lighter toned halo that helps to differenciate them from dunes. dune fracture dune fracture ?

100 m HiRISE mosaic

5 HiRISE mosaic with HiRISE color images 500 m

7 200 m HiRISE mosaic with HiRISE color images This part, on the flank of Mawrth Vallis, have smaller fractures than the other targeted zones of fractures.