Redox-Driven Habitable Environments and a Possible Record of a Temperate Noachian Climate on Mars at Mawrth Vallis
When: November 10, 2015 3PM PST
The plateau surrounding Mawrth Vallis exhibits some of the strongest, most areally extensive, and most diverse clay spectral signatures on Mars. Similarly extensive clay deposits form on Earth due to surface weathering and soil development in sedimentary sequences, forming paleosols. In a paleosol model, the mineralogy at Mawrth is consistent with soils developed under variable drainage conditions, leading to iron and sulfur redox cycling in surface ponds and at groundwater seeps. These reducing environments may be sites of high organic preservation potential. On Earth, these redox reactions are often microbially mediated, and thus may have provided a source of energy for microorganisms on ancient Mars. Furthermore, the clay mineralogy at Mawrth is consistent with soils developed under persistently temperate, rain-dominated climates. If the Mawrth clays are indeed a paleosol sequence, they may provide an easily accessible and continuous Noachian climate record. The Mawrth Vallis region is currently under consideration as a landing site for both the Mars 2020 rover and future human exploration.