A DELTA-LAKE SYSTEM AT JEZERO CRATER (MARS) FROM LONG DISTANCE OBSERVATIONS

Abstract

International audienceOrbital and rover observations of relictgeomorphic features and stratigraphic architectures indicate Mars once had a warmer, wetter climate. Constraining the character, relative timing and persistence of ancient aqueous activity on Mars is possible through detailed interrogation of the stratal geometry of aqueously deposited sedimentary bodies. Such analyses inform interpretations of Martian climate evolution, potential habitability, and search strategies for rocks that might contain potential biosignatures. A prominent sedimentary fan deposit at the westernmargin of Jezero crater has been inferred to be a river delta that built into an ancient lake basin during the Late Noachian-Early Hesperian epochs on Mars (~3.6-3.8 Ga) [1, 2, 3]. The Perseverance rover landed on 18 February 2021 ~2.2 km from the western fan. During the early phase of mission investigations, highresolution images obtained from the Mastcam-Z camera and from the Remote Micro-Imager of the SuperCaminstrument provided the first ground-based observations of the western fan and an associated remnant outcrop, named Kodiak. Here, we report its sedimentology, which provide new constraints on the nature of the fan deposits, and their paleoenvironmental implications (4)