Characterizing the Facies and Stratigraphy of the Enchanted Lake Area in Jezero Crater, Mars

Abstract

Jezero crater contains a sedimentary fan deposit previously interpreted as a delta, which can be studied to better understand the aqueous history of Mars. After a year of traversing and sampling the crater floor, the Mars 2020 Perseverance rover encountered the Enchanted Lake area at the base of the sedimentary fan. Data were collected at Enchanted Lake between sols ∼420–426 and again between sols 556–629 when the rover returned for sampling. The goal of this paper is to describe and characterize the facies within this outcrop to help constrain the paleoenvironment of Enchanted Lake in the context of the overall fan system. Facies are defined based on observed sedimentary structures, bedding geometries, and grain size. The lack of extensive cross-stratification combined with an abundance of soft sediment deformation, planar bedding, and normal grading leads us to interpret Enchanted Lake as a turbidite succession formed in a generally unconfined prodelta environment. Such depositional environments have high preservation potential for organic matter and potential biosignatures. Samples from these rocks have been collected by Perseverance for a planned Mars Sample Return mission. Our interpretation of Enchanted Lake is also consistent with other sedimentary deposits in the Jezero crater, such as the Kodiak butte, which is interpreted as deltaic in origin. Placing Enchanted Lake in context with Kodiak provides some constraints on the relative timing of these deposits within the Jezero fan system.