Nanoscale biosignatures in gypsiferous deposits: implications for Life detection on Earth & Mars

Gypsum stromatolites(GS) make excellent paradigms for the investigation of fine-scale mineral-microbial interactions and for the detection of Life remnants in gypsiferous deposits of Earth and Mars. In this framework and in light of NASA and ESA space missions targeting past traces of Life on Mars, we are studying the geomicrobiology of living and fossil GS from a terrestrial Martian analogue-site at the drylands of Ethiopia (Bakili Lake, Danakil Depression). To map the distribution and characterize the chemical content and structure of micro-/nano-sized inorganic and organic biosignatures preserved in GS we will use SXM combined with multi-elemental μXRF 2D mapping and micro-spectroscopy, i.e., S & P K-edge μXANES, utilizing the unique technical capabilities of the upgraded ID21. Given no such experiments have been previously performed in gypsiferous sediments, we aspire that these results will provide new insights on biosignatures detection in the evaporitic record of Earth & Mars.