Preservation of traces of life under extreme environments mimicking ancient conditions on Mars

David Fernández Remolar, Luleå University of Technology, Sweden | 29 novembre 2018

– Pas de vidéo disponible pour ce séminaire.

The interaction between microbial communities and the geosphere produce several natural entities such as structures and compounds that can be eventually transferred to the geological record in a span of time up to billions of years. They provide essential information in regards to the microbial life which generated them as a result of metabolism (geochemical as mineral and, isotopic) or phylogenetic origin (molecular biomarkers). If life emerged on Mars and assuming that it is founded on the same principles as the Terrestrial life, it may have recorded as similar geobiological traces occurring in the different earthy geological materials. In this regard, the geological record of Mars strongly suggests that most of the ancient, as well as some modern environments, are characterized as extreme systems under terrestrial conditions. As a consequence, the preservation of ancient biological activity in Mars can be evaluated by studying the preservation of the geobiological record in terrestrial analogs replicating the conditions on the red planet. In this seminar, we will discuss different types of biosignatures that have been preserved in some terrestrial analogs of Mars. This will include mineral, structural/textural, geochemical and molecular traces that have been found in acidic, cryptic and hyperarid environments. In some cases, biosignatures have found not only in modern and active extreme environments but also in its geohistoric counterparts that have been recorded as distinctive geological materials.