The Possible Aqueous Origins of Manganese Alteration Minerals in the Máaz Formation of Jezero Crater.

Abstract

Home to a lake around 4 billion years ago, Jezero Crater is a unique location to study the interplay between igneous processes and aqueous alteration on ancient Mars. The Máaz formation, rich in basaltic rock, is the highest stratigraphic unit on the crater floor and hosts a diversity of alteration phases that indicate multiple aqueous episodes affected the crater floor rocks. Using data from the Planetary Instrument for X-ray Lithochemistry aboard the Perseverance rover, we investigated manganese enrichments across the crater floor. We report on multiple distinct types of Mn-rich materials. The first, in the Guillaumes abrasion low in the Máaz formation, has been tentatively identified as the rare mineral despujolsite (Ca₃Mn⁴⁺(SO₄)₂(OH)₆·3H₂O), which forms on Earth in hydrothermal and lacustrine deposits. In the Alfalfa abrasion patch, high in the Máaz formation, we find Mn-enriched magnetite spatially associated with a Ca-dominant sulfate that may contain minor Mn, which suggests a history of serpentinization followed by exposure to oxidizing acidic fluids. These findings underscore the complexity of aqueous alteration over the course of Jezero history. Future sample return missions could refine mineralogical interpretations and provide more information to improve our understanding of aqueous conditions and habitability in the crater.