Abstract_EANA2025-12

Abstract EANA2025-12

Relationship between the western and northern deltas in Jezero crater on Mars and its potential astrobiological significance

Anastasiia Ovchinnikova (1), Ralf Jaumann (1), Sebastian Walter (1), Christoph Gross (1), Wilhelm Zuschneid (1), Frank Postberg (1)

(1) Institute of Geological Sciences, Planetary Sciences and Remote Sensing Group, Freie Universität Berlin, Germany

Understanding the relationship between the western and northern deltas in the Jezero crater on Mars is crucial for the reconstruction of water history in this region. In our study we explore the origin of the LCP/smectite and Olivine/carbonate units, which were found in both deltas [1]. For the northern delta topographical and compositional data show that these units do not represent parallel layering typical for the Gilbert-type delta. Therefore, the upper LCP/smectite unit was emplaced on the already eroded Olivine/carbonates unit. We hypothesize that the LCP/smectite unit is material that was transported from the western inlet through the northernmost channel of the western delta – it is the closest source of this material. We modeled this scenario using equations of the sediment settling velocity (for the vertical movement of sediment particles) [2] and conservation of volumetric flow rate before and after the river enters the lake (for the horizontal movement of the particles). Results show that fine silt and clay will settle at the location where the LCP/smectite unit is found on the northern delta. This increases the astrobiological potential of the northern delta, as fine-grained LCP/smectite sediments could provide nutrients for the possible microbial life in the past. For example, the reaction of low-calcium pyroxene (LCP) with water and carbon dioxide can release iron and magnesium, which are crucial elements for microorganisms. Besides that, smectite clays have interlayer structure which could capture organics and preserve biosignatures.

Our model was also validated using information from the Perseverance rover [3] and THEMIS data.

References:

[1] Horgan, B. H. N., Anderson, R. B., Dromart, G., Amador, E. S. & Rice, M. S. The mineral diversity of Jezero crater: Evidence for possible lacustrine carbonates on Mars. Icarus 339, (2020)

[2] Ferguson, R. I. & Church, M. A simple universal equation for grain settling velocity. Journal of Sedimentary Research 74, 933–937 (2004).

[3] Farley K., and Stack K. Mars 2020 reports, Volume 2, Delta Front Campaign (2023) https://mars.nasa.gov/internal_resources/1656/