Mysterious mounds on Mars

This is at http://phys.org/print306138471.html … mounds of light toned layered deposits surrounded by soft sand and dust are the focus of this piece. The mainstream explanation owes itself to earthbound geological theory. The chasm or scar in the landscape in which the mounds are found was due to volcanic activity – 3 billion years ago. Subsequently, at a later stage, the walls of the chasm collapsed inwards and facturing and faults allowed subsurface water to spill out and pool at the bottom of the chasm. The large mounds inside the chasm consist of sulphate rich material which is apparently an indication the rocks were altered by water. The layering process, it is alleged, was due to a succession of lake deposits in the chasm.