Textures on Mars: evidences of a biogenic environment.

Sediments on Mars could be explained as the result of simple coalescing structures having the ability to produce oriented concretions and more complex forms, as are intertwined filaments of microspherules, laminae and "blueberries", growing from a microscopic scale to a macroscopic one. Of which we have examples in some terrestrial microbial community, especially in regards to cyanobacteria and their organosedimentary products named stromatolites. This study aims to describe the most-often structural features that occur, showing their mutual relations in passing from simple to complex forms. These relationships could explain the genesis and the funny shapes of "blueberries" as the result of two different processes: by an enrolling sheet of microspherules or by an internal growing of minor spherule aggregates.