Formation and Alteration of Olivine‐Carbonate Rocks Within Jezero Crater as Constrained by In Situ Visible/Near‐Infrared Multispectral Images

Abstract Olivine‐ and carbonate‐bearing rocks are key exploration targets on Mars because of the information they can provide about magma evolution and source characteristics, implications for surface water availability and climate, and their biosignature preservation potential. The NASA Mars 2020 Perseverance rover has explored olivine‐ and carbonate‐bearing rocks in the Séítah formation and the Margin unit within Jezero crater, thought to be part of the largest exposures of such rocks on Mars. This study uses Mastcam‐Z red‐green‐blue (RGB) and multispectral (442–1,022 nm) data to assess and compare the Séítah formation and the Margin unit, constrain their potential origins, and determine whether they might share a genetic relationship. Mastcam‐Z data shows that the Séítah formation is a series of layered, olivine‐dominated crystalline igneous rocks, and that the Issole member is more altered and/or more evolved than the Bastide and Caille members, consistent with data from other Perseverance instruments. In the more carbonate‐bearing Margin unit, pervasive alteration complicates the interpretation of its original emplacement mechanism. The unit may be consistent with an igneous deposit(s) that has experienced varying amounts of aqueous alteration and, in the East Margin, sedimentary reworking, possibly related to a past lake in Jezero. Margin unit rocks found at higher elevations on the inner rim are most similar to the Séítah formation and may represent a relatively unaltered component of the Margin unit. The extent to which local versus regional processes have formed olivine and carbonate rocks in this area of Mars remains an important area of study.