The recognition of iron microbial mats in terrestrial environments is of great relevance for the search for extraterrestrial
life, especially on mars where significant iron minerals were identified in the subsurface.
Most researches focused on very ancient microbial mats (e.g. BIFs) since they formed on Earth at a time where
similar conditions are supposed to have prevailed on Mars too. However, environmental proxies are often difficult
to use for these deposits on Earth which, in addition, may be heavily transformed due to diagenesis or even
Here we present modern and phanerozoic iron microbial mats occurrences illustrating the wide variety of
environments in which they form, including many marine settings, ponds, creeks, caves, volcanoes, etc. Contrarily
to their Precambrian counterparts, Modern and Phanerozoic deposits are usually less affected by diagenesis and the
environmental conditions likely to be better constrained. Therefore, their investigation may help for the search for
morphological and geochemical biosignatures (e.g. iron isotopes) in ancient iron microbial occurrences on Earth
but also on other Planets. In particular, many of the case studies presented here show that microstromatolithe-like
morphologies may be valuable targets for screening potential biosignatures in various rock types.